Sunday, 31 January 2016

The Importance of Sleep for Rowers


Its 6am most of the population are tucked up in bed, meanwhile the average rower has already started the warm up for their morning training session.  Success in rowing requires an almost unparalleled level of hard work, determination and self-discipline.  Early sessions on the water in freezing wet weather, intense land training coupled with the stresses of full time work or studies places an exceptional strain on the mind and body.  A key, and often underappreciated, aspect of maximising athletic performance is sleep. We could be excused for disregarding the importance of sleep, with stories from successful people like Nikola Tesla, Barrack Obama and Marissa Mayer getting by on just a few short hours.  Thomas Edison was notoriously quoted as saying “Sleep is a criminal waste of time and is a heritage from our cave days” and slightly more bluntly Maggie Thatcher simply said “Sleep is for wimps”.  However a disregard for sleep has the potential to derail even the most talented athlete.  As little as 3 hours of sleep restriction for one night has been shown to negatively impact exercise performance, reaction time, decision making, alertness and increase lactic acid and catecholamines (stress hormones) concentration.  Also perhaps in a cruel sense of irony increased training loads are associated with poor quality of sleep.  Elite athletes treat their sleeping habits like they do all other aspects of their training and lifestyle, they seek optimisation so peak performance can be achieved. 

Sleep Infographic credit to YLM Sport Science 


Usain Bolt 8-10 hours  
"Sleep is extremely important to me.  I need to rest and recover in order for the training I do to be absorbed by my body,"


Andy Murray up to 12 hours
"On the days when I am not playing I try to get in and do my work early, deal with ­everything else that has to happen, and then get home and have a nap.  I don’t normally have any ­trouble sleeping. I sleep well. You need rest to make sure you ­recover properly."

Roger Federer 11-12 hours
"If I don’t sleep 11-12 hours a day, it’s not right,"                                      

Larry Fitzgerald
"I always get my rest and I think that's one of the things that people don't talk often about. Your body heals and repairs itself better than anything. Being able to get some sleep really does a great cause for your recovery and helping you wake up with a renewed, fresh mental and physical outlook."

The Importance of Sleep
Sleep is defined as a homeostatically controlled behavioural state of reduced movement and sensory responsiveness.  The underlying mechanisms as to why sleep is so essential boil down to two main aspects. 
  • It has a restorative effect on both the immune and endocrine systems
  • It plays a role in cognition with links to memory, learning and the strengthening of the connections between neurons commonly referred to as synaptic plasticity.


When we sleep we got through multiple 90 minute sleep cycles, these cycles comprise of rapid eye movement sleep (REM) and non-REM sleep. Growth hormone and other anabolic hormones have been shown to be produced during N-REM.  Sleep restriction to 5 hours per night for one week reduced testosterone levels by 10-15% in young healthy males.  These hormones are of course essential for tissue regeneration and growth, but they also mobilise fatty acids to provide energy thereby preventing the loss of muscle.  This process is particularly important for rowers who are require rapid healing and repair, to deal with the intense training schedule.  On the other hand REM sleep is linked to brain activation and emotional regulation.  Both stages of the sleep cycle have been implicated in sleep dependant memory formation, and more specifically has been shown to effect ability in tasks related to physical movement.  Rowing requires a high level of mental discipline and concentration to maintain technique under extreme physical stress, therefore the cognitive benefits of getting enough sleep is just as important as the physical.  

Sleep Duration
So how much sleep do we need?  This is a complex question as there is a huge amount of inter-individual variability especially when it comes to athletes.  Generally a minimum of 8 hours is recommended, however athletes may require more.  Increasing sleep duration to 10 hours per night for 5-7 weeks in basketball players, increased their sprint time, shooting accuracy and reaction time.  A recent study in young men and women preparing for the world junior rowing championships, found that an increase in training negatively impacted sleep quality and duration.   This lead to reduced ratings of overall recovery and greater scores on a test of negative emotional state.  When training was reduced in the second half of camp sleep duration increased to 8 hours and scores of recovery and stress subsequently improved.
Infographic Summary for Study in Junior Rowers credit to YLM Sport Science 

Enhancing Sleep Quality
Getting good quality sleep is just as important as the total duration of sleep or time in bed.  This comes down to two main factors, sleep onset and preventing disturbances.

A substantial consideration for onset of sleep is light exposure, or rather exposure to particular wave lengths of light.  The circadian rhythm is a daily cycle of biological activity which includes sleep, controlled by the suprachiasmatic nucleus within the hypothalamus, and it is heavily influenced by exposure to light and dark.  The modern era has brought with it a number of technological advances including laptops, tablets and smart phones.  These devices emit a short wavelength enriched light, meaning they have a higher concentration of blue light than natural light.  Blue light has been shown to reduce levels melatonin, a hormone secreted by the pineal gland that is associated with the onset of sleep.  Over exposure to blue light from our devices can upset the sleep wake cycle and delay the onset of sleep.  This can be avoided by reducing exposure to these devices later in the day or by using blue light filters such as FLUX.  Making the bedroom as dark and quiet as possible can also help with the onset of sleep and reducing sleep disturbances.

Nutritionally there is some evidence to support strategies for preventing disturbance and enhancing onset of sleep.  The neurotransmitter 5-hydroxytryptophan is a metabolic intermediate in the biosynthesis of serotonin and melatonin.  Production of this neurotransmitter is dependent on the availability of the amino acid tryptophan.  Tryptophan needs to be transported over the blood brain barrier (a semipermeable membrane separating the blood from the cerebrospinal fluid), however the branch chain amino acids are preferentially transported ahead of tryptophan.  Branch chain amino acids play an important role in muscle growth and recovery, therefore athletes are recommended to consume foods rich in these amino acids (Meat, dairy and legumes).  Transport of tryptophan across the blood brain barrier can be enhanced by consuming a carbohydrate rich meal, stimulating insulin secretion which facilitates the transport of branch chain amino acids into muscle tissue resulting in increased free tryptophan.  A study conducted investigating this theory comparing high and low glycaemic index (GI) carbohydrate ingestion.  Consuming a high GI meal 4 hours before going to bed was found to be optimal compared to 1 hour before bed and low GI feedings at identical time points.  So judging by this evidence it would appear that consuming a meal containing high GI foods (e.g. white rice, potato and pasta) could enhance sleep quality, as long as it is consumed more than 1 hour before going to bed.  This is great news for rowers as if there is one thing rowers love its carbs.   

Summary


To conclude sleep is essential for performance and recovery in rowing.  It impacts both physiological and cognitive aspects and can be influenced by a number of environmental factors such as light exposure, training load and nutrition.  Optimising sleep environment, reducing blue light expose and imposing proper nutritional strategy could positively impact sleep onset, duration and quality and thereby positively influence training environment and competitive performance. 


References

Doran, S., Van Dongen, H. and Dinges, D. (2001). Sustained attention performance during sleep deprivation: evidence of state instability. Arch Ital Biol., 139(3), pp.253-67.

Fullagar, H., Skorski, S., Duffield, R., Hammes, D., Coutts, A. and Meyer, T. (2014). Sleep and Athletic Performance: The Effects of Sleep Loss on Exercise Performance, and Physiological and Cognitive Responses to Exercise. Sports Med, 45(2), pp.161-186.

Halson, S. (2014). Sleep in Elite Athletes and Nutritional Interventions to Enhance Sleep. Sports Med, 44(S1), pp.13-23.

Harrison, Y. and Horne, J. (2000). The impact of sleep deprivation on decision making: A review.Journal of Experimental Psychology: Applied, 6(3), pp.236-249.

K├Âlling, S., Steinacker, J., Endler, S., Ferrauti, A., Meyer, T. and Kellmann, M. (2016). The longer the better: Sleep–wake patterns during preparation of the World Rowing Junior Championships.Chronobiology International, pp.1-12.

Leproult, R. (2011). Effect of 1 Week of Sleep Restriction on Testosterone Levels in Young Healthy Men. JAMA, 305(21), p.2173.

Mah, C., Mah, K., Kezirian, E. and Dement, W. (2011). The Effects of Sleep Extension on the Athletic Performance of Collegiate Basketball Players. SLEEP, 34(07), pp.943-950.

Takahashi, Y., Kipnis, D. and Daughaday, W. (1968). Growth hormone secretion during sleep. Journal of Clinical Investigation, 47(9), pp.2079-2090.

Weitzman, E. (1976). Circadian Rhythms and Episodic Hormone Secretion in Man. Annual Review of Medicine, 27(1), pp.225-243.


Thursday, 10 December 2015

Coffee and Health Part 1 – What is in coffee and how does it work?



It’s one of the most sought after commodities in the world right up there with crude oil and natural gas.  Whilst the former products are used to power cars, planes and industrial factories the humble coffee bean powers us human beings through the latest deadline, early morning, hangover or workout.  In the UK it’s estimated that we consume 70 million cups of coffee each day.  In recent years there has been a substantial growth in businesses specialising in coffee.  The turnover for these outlets was 6.2 billion pounds in 2013, a 6.4% growth from 2012, and 800,000 Britons report visiting a coffee shop at least four times per week.  This upward trend in the consumption of espresso style coffee substantiates the requirement to better understand the health implications of coffee, and the bioactive compounds in coffee.

I believe I come at this topic from a relatively unique perspective.  Not only have I got a fairly deep understanding of the hard science behind coffee and caffeine, I have also worked in a coffee shop on and off throughout my school and university years for eight years.  If I had to count the number of cups of coffee I have made it would most certainly be in the thousands, and similarly I have read hundreds of peer reviewed research articles on coffee.

So a little bit of background on coffee before going into the mechanics of how it does what it does.  Despite it now being grown in a number of countries, coffee originated in Ethiopia.  The coffee blend used to make your morning cuppa will always consist of Arabica beans which may also have added to them Robusta beans.  Arabica beans are very flavourful with less caffeine and tend to grow at higher altitude in comparison to Robusta beans.  Robusta beans are much more bitter and acidic than Arabica and contain much more caffeine, usually 50% or more, and typically grow at lower altitude.  The role of caffeine in plants is actually as a pesticide, hence robusta beans in lower areas have greater concentrations to protect the plant against a greater number or insects.

Coffee and caffeine typically go hand in hand how often have we heard the phrases “I need my caffeine fix”.  There is good reason for this caffeine has the predominant effect out of all the compounds in coffee.  Anyone who has had a strong cup of coffee will have felt that stimulant effect, that buzz that comes from consuming caffeine.  So I will now seek to explain what caffeine actually does in the body. 
The Formula of Caffeine 
When we look at the effects of any substance on the human body it’s important to consider the precise mechanisms of what is actually going on, to full understand the effect it is having.  This means getting quite deep into the science however I will try to make to make it as easy to read as possible.  The primary mechanism of caffeine is to act as an antagonist for adenosine receptors, more specifically the A1 and A2a receptors.  What this means is that caffeine binds to the adenosine receptor sites, therefore preventing adenosine from doing so.  Imagine coming into work to see a life size cardboard cut-out of yourself siting in your office, yes it may look like you and occupy the same space, but that doesn’t mean it can actually do the same job (having said this some days I feel a cardboard cut-out may be just as productive as me!).  This is essentially what happens with caffeine, on a molecular level it is structured very similarly to adenosine, so it binds to the same receptor sites but it can’t actually cause the same action that adenosine would.  
Caffeine Binding to Adenosine Receptor Sites  
The regular function of adenosine is to dilate coronary heart vessels, promote sleep, supress arousal and decrease renal blood flow.  Antagonism of adenosine receptors plays an important role in affect caffeine has on cognitive performance, alongside the inhibition of benzodiazepine receptor ligand (another neurotransmitter that slows down brain activity). Caffeine intake causes increases in neurotransmitters, including noradrenaline, dopamine, acetylcholine, glutamate and gamma-aminobutyric acid.  The increase in these neurotransmitters is what causes the “caffeine high” or “caffeine buzz”.  The net effect is a temporary increase in blood pressure and arterial stiffness, a feeling of alertness or stimulation and a mild diuretic effect.  Chronic consumption of caffeine leads to an up regulation in number and activity of adenosine receptors, also referred to as caffeine adaption.  This is the principle reason why habitual and non-habitual consumers tend to react differently to caffeine in studies.  It is also the reason why regular caffeine consumers often see themselves slowly increasing their intake.  As their body adapts they require more caffeine to get the same “buzz”.

The Structure of Caffeine Versus Adenosine
Another important consideration is the metabolism of caffeine, or the way the body processes caffeine.  Caffeine is absorbed rapidly from the small intestine, and is highly bioavailable.  It reaches peak plasma concentrations 30-45 minutes after consumption, and is delayed with food ingestion. Caffeine is metabolized into more than 25 metabolites in humans, mainly paraxanthine, theobromine, and theophylline.  Seventy two to eighty per cent of the metabolites from caffeine metabolism are paraxanthine.  Cytochrome P-450 1A2, located in the liver, is responsible for ≈ 95% metabolism in humans.  There are variances in the genes encoding for the enzymes that metabolise caffeine, this means that individuals will metabolise caffeine at different rates.  The normal half-life of caffeine is around 2.5-5 hours.  This means that if you consume 200mg of caffeine 2.5-5 hours later there will only be 100mg left in your system.  Carriers of the *1F allele variant metabolise caffeine slower than average, whereas carriers of the A2*1A gene metabolise caffeine at a higher rate.  Studies in regular caffeine consumers have often found increased activity of CYP1A2a, so they metabolise caffeine much quicker compared to non-caffeine consumers.  In fact the half-life of caffeine in these individuals have been reported to be as low as 1 hour.  Again in regular caffeine consumers, variances in the loci near BDNF and SLC6A4 have been detected which could impact consumption patterns by modifying the acute behavioural and reinforcing properties of caffeine.  So these consumers have genetic variances that actually make caffeine consumption seem more pleasurable.
A final factor (for now) when looking into this topic when it comes to coffee is, although caffeine is the main bioactive compound in coffee, there are a ton of other substances in there too!  Other important compounds in coffee include quinic acid, chlorogenic acid, citric acid, phosphoric acid, acetic acid, cafestol and kahweol.  Furthermore not every cup of coffee is created equally variances in blends, roasting process and preparation methods all impact the amounts of caffeine and other compounds in a cup of coffee.  This makes it difficult to thoroughly pool the research together, and draw definitive conclusions.  I have found that preparation method is something that is only staring to be considered in the research.

So there we have it a bit of back ground on coffee and caffeine, how it’s metabolised and what it’s actually doing in the body.  Coffee and caffeine remains a poignant focus of research for good reason.  It’s consumed in vast quantities and there are a number of questions that remain on its effect on short and long term health and performance.  What I’m hoping to do with these series of blog articles is bring evidenced based information on this debated, topic and hopefully provide some answers.  Stay tuned for the parts 2-4 which will be cardiovascular health and heart disease, sports performance and cognitive function. 

Sunday, 9 August 2015

The Future of Meat


I recently attended the Nutrition Society Summer conference entitled “The future of animal products in the diet.”  The conference was fantastic there was a huge diversity of speakers, coming at the issue’s from a myriad of perspectives.  The combination of informative presentations on the latest scientific research and lively debate, combined with a friendly “in it together” atmosphere made for a uniquely positive environment that I found to be very inspiring.  I am going to attempt to sum up, and give my opinion on, some of the main topics.

Is eating meat healthy?
A lot of the talks were focused around the health implications of eating meat.  This involved looking at some of the individual nutrients in meats and epidemiological trends in disease incidences.  As most of us know meat is an excellent source of protein containing both essential and non-essential amino acids.  Depending on the type, meat can also be a good source of several micronutrients including magnesium, zinc, iron and B12.  Its certainly true we can also get these nutrients from plant sources however, the proteins and micronutrients in meat are highly bioavailable.  An excellent example is heam iron, which has a bioavailability of around 20-30% whereas iron found in plants is only around 5%.

A topic that came up several times was the health implications of consuming saturated fat, of which meats, alongside dairy, contribute a significant percentage to our diet.  The general consensus was that that saturated fat seemed to have a neutral effect on cardiovascular disease mortality incidence and risk markers.  If you want to know more I have written an article on this HERE.  Omega 3 was also talked about in depth.  Consuming adequate amounts of omega 3 should be, in my opinion, a huge priority in public health campaigns.  Again I have more details on Omega 3 HERE.  An advantage of meat consumption that kept cropping up was that animal sources of omega 3 are already in the active forms, EPA and DHA.  Humans have an extremely limited capacity to convert the 18 carbon omega 3 fatty acid alpha linolenic acid, found in plant sources like flaxseed, to the longer chain omega fatty acids EPA and DHA.  At this point I want to point out that we eat whole foods we don’t just consume single nutrients.  Although saturated fat may not have a significant influence on cardiovascular disease as we first thought, if you consume lots of salami containing high amounts of salt and nitrates this could be detrimental. 

When it comes to meat and disease incidence processed meat appears to be the bad guy.  High consumption of processed meat was linked to cardiovascular disease, stroke, diabetes and certain types of cancer.  A large question mark here is what exactly is defined as processed meat?  For example a question was raised as to the effects of processed fish, this appeared to highlight a gap in the current knowledge base.  For me this means trying to stick to whole cuts of fresh meat, and if you’re unsure ask your butcher they should be able to tell you exactly what has or hasn’t been done to their product.

Meat farming practices, feeding
In an effort to make farming meat more sustainable and the product more nutrient dense, there has been a lot of work done on feeding practices.  This is something humans have been doing for years essentially trying to get an animal’s weight to increase quicker.  This has been done through selective breeding of animals with a better feed efficiency (able to put on weight with less food).  It was explained in one of these lectures that feeding cows fish oil or micro algae was being used to increase the EPA and DHA content in beef.  For me I feel like this is adding an extra step that isn’t required if we just eat seafood.  If I wanted to go to London from Edinburgh I wouldn’t go via Moscow!  Slight hyperbole but I think that’s what we are doing here.  It’s quite sad that as a population we are so adverse to consuming fish that feeding cattle fish oil is what we are turning too.  Moreover the EPA and DHA content of this enhanced meat still paled in comparison to what is in fish.  From a sustainability stand point I don’t think this makes sense either, a lot of oceans are over fished so why give these fish to cattle to produce a beef product that has less EPA and DHA compared to the original fish.  On the other hand micro algae may be a slightly more promising option as at least this can be grown fairly easily, but again I just think people should try and eat fish.  Another issue with these find of changes to farming practices is it is unlikely that farmers would be able to implement any of these strategies without some sort of financial backing.

Meat Sustainability Carbon Footprint
This was a big topic during the conference.  The world’s population is expanded at a rapid rate growing around 1.14% each year.  This raises huge questions on how we are going to efficiently feed this expanding population.  To compound this we have the issue of global warming.  Now I am not an expert in this area at all and won’t pretend to be.  Producing meat on the scale we currently do has a huge carbon footprint and requires vast quantities of water.  We need to produce the feed itself, transport the animals and meat and also the animals have an impact themselves particularly cows due to the amount of methane they produce.



It has become a bit of a joke but cows do produce a lot of methane especially if you consider the fact that there is around 1.4 billion cows.  What is less funny is this image of an industrial farm in the states.  That green coloured "pit" in the middle is a whats known as a "waste lagoon".

Going forward this has to change and the solutions appear to be an overhaul of farming practices or reduce the demand i.e. eat less meat.

What should we do?
One of the best quotes from the conference was in my opinion….
"We don't need to demonise meat, but we should recognise its cost” - Professor Tim Benton
Personally I don’t think we should all become vegetarians.  I enjoy eating meat and it is a great source of several nutrients.  What I do support is a reduction in meat consumption and a mindfulness of what types of meat we are consuming and where it’s coming from.  I think western populations are often guilty of constantly wanting more more more, and this just isn’t sustainable.  The food and agricultural industries have a huge role to play moving forward as we seek to make meat consumption a more viable long term option.  However we as consumers need to take some responsibility for our current predicament and make some changes to our eating habits

So what can we do?
·      
        Cut down on meat and consume more alternative protein sources - Current recommendations from the British Nutrition Foundation is to consume a maximum of 80g of meat per day.  Beans, legumes and pulses are all good sources of protein and are high in fibre.  Several meat alternatives exist too such as Quorn and hey if it’s good enough for Mo Farah.  I have to admit I didn’t have a particularly high opinion of Quorn but a talk from Dr. Tim Finnigan educated me on the food product, highlighting that Quorn is a complete protein with a high bioavailability (actually higher than some meat products). 

·      Prioritise fresh cuts of meat over highly processed products, and shop local.  Processed meat was consistently shown to have a negative impact on health.  By buying fresh cuts you are looking after your health and, if you buy from a butcher, you are supporting a local business.
·       Spend the same but buy less – go for quality of quantity and look for sustainably sources meat products.  Companies are usually quick to advertise if their meat is sustainable it just takes a little time to check over the labels.

·      Eat the whole animal – A mantra I have lived by over the last couple of years is if I am going to eat meat I am going to make an effort to consume a mix of cuts.  This includes eating organ meats on a fairly regular basis.  These are cheap and extremely nutrient dense and there is a ton of recipes out there to get them into your diet.  WARNING organ meat tends to be very high in vitamin A so it wouldn’t be advisable for anyone who is pregnant to consume any more than once per week.

·       Try eating some wild caught game – This is tricky to come by in the UK but its a much more sustainable meat.  The animal is usually fed on its natural diet and game tends to be both lean and nutrient dense venison being an excellent example.

Eating insects


There was a talk from Professor Arnnold van Huis, co-author of “the insect cookbook”.  At first, to me, this seemed like it was going to be a talk about the “novel” idea of consuming insects.  It turns out this is a legitimate option that many countries have already adopted.  Farming insects is a relatively easy and very sustainable practice, which has been practiced across regions of Asia for a number of years.  These insects can be fed to animals or consumed by humans, and are a source of protein and nutrients.  Supermarkets in the Netherlands have already started selling certain varieties of insects and cricket flour can easily be purchased from online retailers.   The issues moving forward here in the UK is ticking all the boxes on food regulations, but it seems the ball has been set in motion on this.  Another big issue is just getting past the notion of eating insects, which in western cultures is generally thought of as well a bit weird.  I will certainly be interested to see if insects hit our supermarkets in the future and how they will be received.  Professor  Van Huis has actually done a Ted Talk and it can be viewed here.


Rather than conclude with a lengthy statement I’ll just sign off with this video which I think sums up the sustainability of meat quite well.  I will say that personally I probably am going to cut down my meat consumption a little, especially processed meat.  I am into my sport and I enjoy training and with that always comes the importance of consuming high quality protein.  By spending the same and eating less, focusing on sustainably sourced meat and alternative protein sources even as a fairly active person I don't think I have anything to worry about regarding protein intake.



Saturday, 20 June 2015

Indulgence




Indulgence and Binging
At one point or another we’ve all indulged in some less than ideal food choices, or in some cases gone on an all-out food binge devouring everything insight until a state of food coma is reached.  The food we indulge in will vary between individuals it may be massive curry, a slab of cheese cake or anything in between.  Unfortunately what follows is often an overwhelming feeling of guilt, reinforced by some physiological “symptoms” of overindulgence water retention, lethargy, mind fog etc. can all occur.  My opinion is we should be able to treat ourselves every now and then and not have to feel this way, it’s about maintaining balance and viewing food as an experience.  So here are some insights and tips from me when it comes to treating ourselves.

Be Mindful of What You’re Doing
This article isn’t designed to be an all access pass to the Chinese buffet, it’s about making conscious decisions on what we are doing and if it’s constructive towards our goals.  If your goal is fat loss and you overindulge therefore going above you calorie threshold, it’s important to be aware that what you’re doing isn’t constructive in terms of your individual goal.  However fat loss doesn’t boil down to individual days it’s about consistency over weeks, months or even years.  So going out with friends and having a burger with fries and milkshake on occasion won’t suddenly make you pile on the pounds, as long as you are consistent throughout the rest of your diet.  Just because you are dieting doesn’t mean you should miss out on social experiences and good food.  The problem tends to arise when this becomes and all too regular occurrence, this is when progress starts to slow down or regression occurs.  To wrap up this point be conscious of your decisions to indulge, how often it’s occurring and if it’s constructive, but don’t feel guilty about experiencing food and being social when the time comes.    

Pre Plan and Really Make the Most of it
This is a fairly subjective point, what you chose to indulge in is your own provocative but this is what I like to do.  If I’m going to indulge I usually try and plan to do so on social occasions whether it’s a family meal, a celebration or something of that nature.   These occasions are meant to be enjoyed and I don’t want to take away from the experience by worrying too much about my calories or macros.  Another time you may want to consider pre-panning your indulgence is scheduling re-feeds whilst dieting.  There is evidence that occasionally increasing calories whilst dieting can actually be helpful in terms of preserving lean tissue and losing fat.  The degree to which these are necessary, the frequency and the caloric intake will vary depending on individual psychology, physiology and goals.  For example someone who has had previous issues with food binging probably should be careful regarding the use of these days, or  for someone who has a degree of insulin resistance or issues managing blood sugar it may not be optimal for them to include re-feeds too often.
If you are going to indulge I think it’s important to make the most of it.  Splash out on some quality ingredients and foods to maximise taste and experience.  I’m always plugging the message of eating whole foods, and I believe that should apply to when we are treating ourselves too.  I’d much rather treat myself to good quality beef burger with bacon on homemade bread with sweet potato fries than on a MacDonald’s meal.  I know for a fact that I am going to enjoy the taste of that burger much more and it’s still going to be providing me with a lot of nutrients.  You’ve been working hard on your diet so when you’re treating yourself treat yourself right.
VS.

 Difference between Indulgence and Binging
It’s important to differentiate between a bit of a treat and an all-out binge.  As you can tell I am all for the occasional treat or re-feed but all out binges not so much.  The problem with all out binges is…
1.  They are often not planned, they tend to be impulsive due to severe hunger or cravings
2.  They lead to extreme caloric surplus which can be detrimental to weight loss goals
3. The “food hangover” the next day is much more severe with more guilt
4. Often one binge can lead to another supporting yo-yo dieting
To avoid food binging it’s important we understand why we sometimes get this insatiable need to eat copious amounts of food.  I think the most common reason is over restriction of calories or carbohydrate.  When we restrict energy or carbs it’s possible to experience hypoglycemia (low blood sugar).  When we have low blood sugar our bodies react by craving foods high in sugar, it needs that instant hit of fast absorbing carbs to maintain homeostasis.  This is why food binges tends to mainly consist of foods high in both refined carbohydrate and calories.  My tips for avoiding this again comes back to being mindful and thinking about what’s going on in your body.  If you’re having these crazy cravings recognise that you may be over restricting your calories or carbohydrate, solution consume an extra 100-300 calories from whole food carb sources such as potatoes, brown rice, quinoa, squash or fruit.  This should give your body the carbs and energy is shouting out for without the unplanned 3000kcal surplus.  Again don’t feel guilty about these extra carbs and calories, your body is showing signs of over restriction, and the added calories will likely not take you out of a caloric deficit.

Tips for the day after
So you’ve decided to treat yourself and the next day you’re not feeling too great. 
1.       Just to reiterate don’t feel guilty this can lead to unhealthy relationship with food, when really food is awesome
2.       Do something active go for a long walk or exercise
3.       Drink plenty of water, usually excess salt and sugar leads to water retention so we need to make sure we stay hydrated
4.       Don’t starve yourself to “make up for it” this will only lead to potential hypoglycaemia and another binge/cheat.  Sure have a lighter breakfast for me I usually have one less egg or 25g less oats nothing too restrictive.
So there we have it my thoughts on food indulgence.  To sum up yes its ok to indulge every now and then, try to avoid binging, be mindful and favour quality whole foods evening when treating yourself. 


Wednesday, 27 May 2015

Insulin


In an earlier article I talked about the importance of focusing on nutrient density and quality and not just calories.  The first law of thermodynamics essentially boils down to:

Energy in (from food)-energy burned (physical activity and other metabolic processes) = energy balance

So if energy balance is positive, we gain weight and if it’s a negative we lose weight.  This has been the basis for many nutritional programmes whether the aim is to gain or lose weight.  I'm not here to argue with this rule as it’s completely correct, we must consider caloric intake for nutritional strategies.  What I do want to discuss is another major consideration we need to make when it comes to the food we eat.  The biological processes in our body are regulated by a number of hormones, and it’s important to understand these hormones and their functions for health, body composition and performance.  I am a strong believer that a better understanding of our bodily processes will lead to us making more positive diet and lifestyle choices.  In short knowledge is power. 
A hormone that most people will recognise is insulin.  Insulin one of the hormones responsible for the metabolism of carbohydrate, amino acids and fats.  It is a peptide hormone that is produced in the beta cells in the pancreas.

How it works
When carbohydrate is digested it enters the blood stream, this triggers both the synthesis and secretion of insulin from the beta cells.  To go a little deeper into the mechanism glucose in the blood stream stimulates calcium ions to move into the beta cells, thus triggering a calcium-dependant exocytosis of insulin through microtubules releasing it into the blood stream.  Amino acids, particularly leucine, fatty acids and ketone bodies have all been shown to exert a weak stimulation of insulin secretion, however these are dependent on the presence of glucose in the blood to be effective.
Insulin has many functions, however its main role is to act as a transporter for glucose into cells.  Glucose is an energy source for all cells in the human body.  Skeletal muscle, cardiac muscle and adipose (fat) tissue are heavily reliant on insulin to deliver the glucose they require.  Insulin stimulates the translocation of glucose transport type 4 (GLUT 4) from within cells to the outside membrane allowing it to accept glucose and transport it into the cell.
So when we consume carbohydrate, blood glucose levels rise, insulin is secreted and glucose is taken up by the cells to be used as energy.  The body is constantly working to maintain a stable blood glucose level of around 4mmol/l.

Diabetes
The condition most associated with insulin is diabetes.  There are two main types of diabetes type 1 and type 2.

Type 1 is characterised by a loss of beta cells in the pancreas therefore reducing the organs ability to secrete insulin.  The condition is usually a result of an autoimmune reaction.  It generally develops in childhood or early adulthood, and requires treatment with exogenous (from outside the body) insulin.

Type 2 occurs as a result of cells becoming insulin resistant, which I will go on to explain in more detail.  It normally presents in adulthood, however it is becoming more frequently diagnosed in children.   Type two diabetics can sometimes go on to require insulin to manage their condition.  Type 2 diabetes makes up around 90% of all cases of diabetes.

Glycemic Index and Glycemic Load
When discussing insulin and nutrition glycemic index and glycemic load is often brought up.  According to Diabetes UK the glycemic index is “A ranking of carbohydrate-containing foods based on the overall effect on blood glucose levels. Slowly absorbed foods have a low GI rating, while foods that are more quickly absorbed have a higher rating.”  The scale goes from 0-100 with pure glucose being 100.  They define glycemic load as “A measure that takes into account the amount of carbohydrate in a portion of food together with how quickly it raises blood glucose levels.”  I quite like this is a measure, as it considers both the type of food and the portion size.  A low glycemic load is between 0-10, medium 11-19 and anything above 20 is considered to have a high glycemic load

Insulin Sensitivity/Resistance
So I have already mentioned the term insulin resistance so let’s delve into what it is.  Insulin resistance is a state in which the cells response to insulin is impaired.  As a result glucose cannot enter the cell and blood sugar levels remain elevated.  Now because blood glucose levels remain high the body reacts by creating and secreting more insulin, so now we have elevated levels of both blood glucose and insulin (hyperinsulinemia).  The pancreas will continue to release insulin until blood sugar levels drop back down to within normal limits.  With insulin resistance it’s not a case of you have it or you don’t, individuals will vary on a scale between being insulin sensitive and insulin resistant.  When someone has high insulin sensitivity it’s like insulin is communicating with the cells on the latest 4G smartphone, whereas being insulin resistance is not unlike the two bean cans tied together with string.  I should also point out our insulin sensitivity varies depending on a variety of factors including time of day, diet and training stimulus.

Insulin resistance is associated with an increased risk of a number of health conditions including diabetes, hypertension, atherosclerosis (a precursor to coronary heart disease), obesity and polycystic ovaries.

There are several genetic risk factors for insulin resistance, however diet and lifestyle plays a huge role in both the development and management of the condition.  Being overweight or obese and/or having a diet high in refined carbohydrate significantly increase the risk of an individual becoming more insulin resistant.  In terms of prevention a healthy balanced diet with an emphasis on single ingredient whole foods, alongside regular activity is certainly the way to go.  When an individual is already to some degree insulin resistant the dietary strategy becomes a little more complicated and debated.  Most recommendations are that when consuming foods rich in carbohydrate aim for those with a lower glycemic index (e.g. brown rice, beans, pulses and oats).  There is also evidence to support the use of low or moderate carbohydrate diets to manage and even reverse insulin resistance.  The purpose of this article is not to debate the varying dietary strategies, if you or someone you know is found to be insulin resistance or diagnosed as pre-diabetic, advice should be sought from primary care providers as dietary strategies should be ideally tailored on an individual basis.
Low Glycemic Index Foods
So to sum up here what we generally want is to maintain a high degree of insulin sensitivity and less insulin resistance.  To test for insulin resistance an oral glucose tolerance test can be performed.  This involves consuming a glucose drink in a fasted state and monitoring blood glucose levels before ingestion and 30, 60 and 120 minutes post ingestion.  The speed at which the body lowers blood glucose levels back to normal indicates how inulin sensitive or resistant an individual is.

Insulin as an Anabolic Hormone 
The final thing I wanted to touch on in regards to insulin is its use as an anabolic hormone.  Because insulin facilitates the transport of carbohydrate and amino acids into the cells it promotes an anabolic environment, as well as preventing catabolism.  It is essentially delivering your muscles the fuel they need to perform, recover and grow.  Strategically manipulating insulin is something body builders and athletes have been doing for years.  This is normally achieved by consuming fast acting (high GI) carbohydrate before and/or after work outs.  Now I would be completely naive to ignore the fact that insulin abuse is a problem in the body building community.    To take advantage of the anabolic properties of insulin some body builders give themselves insulin injections.  It’s certainly not something all of them do, however a survey of 450 body builders found that 10% admitted to abusing insulin.  This is extremely dangerous, it can cause hypoglycaemic events, pancreatitis, coma and even death.  So unless you require insulin for a medical reason, the risk of injecting more far outweighs any potential benefit.

So there we have a quick whistle stop tour about insulin and its role within the body.  Hope you enjoyed it.

References

Accurso, A., Bernstein, R., Dahlqvist, A., Draznin, B., Feinman, R., Fine, E., Gleed, A., Jacobs, D., Larson, G., Lustig, R., Manninen, A., McFarlane, S., Morrison, K., Nielsen, J., Ravnskov, U., Roth, K., Silvestre, R., Sowers, J., Sundberg, R., Volek, J., Westman, E., Wood, R., Wortman, J. and 
Vernon, M. (2008). Dietary carbohydrate restriction in type 2 diabetes mellitus and metabolic syndrome: time for a critical appraisal. Nutr Metab (Lond), 5(1), p.9.

Davies, A., Blakeley, A., Kidd, C. and McGeown, J. (2001). Human physiology. Edinburgh: Churchill Livingstone.

Diabetes.co.uk, (2015). Diabetes UK, UK Diabetes Resource, Diabetes Symptoms, Diabetes Diet, Gestational Diabetes. [online] Available at: http://www.diabetes.co.uk/ [Accessed 25 May 2015].

Evans, P. (2003). Insulin as a drug of abuse in body building. British Journal of Sports Medicine, 37(4), pp.356-357.

Fox, S. (1996). Human physiology. Dubuque, IA: Wm. C. Brown.

Kumar, P. and Clark, M. (n.d.). Kumar & Clark's clinical medicine.

Westman, E., Yancy, W., Mavropoulos, J., Marquart, M. and McDuffie, J. (2008). The effect of a low-carbohydrate, ketogenic diet versus a low-glycemic index diet on glycemic control in type 2 diabetes mellitus. Nutr Metab (Lond), 5(1), p.36.