Intermittent Fasting for Athletes

Image courtesy of www.afl.com.au

Intermittent fasting is by far the diet that I get asked about the most. The word ‘diet’ is often associated with a short-term fad, however intermittent fasting (IF) has indeed become a way of life rather than a quick fix for many individuals. But is this approach suitable for athletes?

Last year I was interviewed for an AFL article on this very topic, as a number of senior AFL players were reportedly pursuing IF as a high performance nutrition strategy.

The link to the article is below - it doesn’t cover every aspect of IF so please get in touch if you are interested in more individualised advice to suit your needs, as everyone is different. Am I a fan of IF? It depends……

Why You Can’t Meet Jack Viney for Breakfast as published on www.afl.com.au

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Vegan vs Keto - for Athletes

Beautiful meal at Trofeo Estate Mornington Peninsula - unintentionally vegan vs keto!

Vegan. Keto.  Two approaches to food and nutrition that in principal could not be further apart, but are promoted by their respective loyal followers as the only way to eat.  Promises of weight loss, mental clarity, digestive health, improved performance and a range of health benefits - clever marketing may convince even the most well-read individual of the benefits of plant-based or carnivorous consumption.

I work with people who follow a vegan lifestyle.  I also work with individuals who are interested in a keto approach.  Both have pros and cons. Yes, there are significant differences, but also similarities that align with universally agreed healthful nutrition strategies - inclusion of vegetables for example.  Neither are fads and both dietary preferences will be with us for many years to come, as will the debate over which style is superior for associated health benefits.  But is one or the other superior for athletes and sports performance?  The type of athlete, and person, you are may be the key to determining whether plant-based vegan or carnivorous keto is the way to go - or something else entirely.    

Vegan virtuosity

‘Veganism is a way of life that seeks to exclude, as far as is possible and practicable, all forms of exploitation of, and cruelty to, animals for food, clothing or any other purpose’ (The Vegan Society).  

Vegan is a lifestyle rather than a diet. There is an increasing trend towards plant-based eating, with significant research supporting the benefits from a health perspective.  The spotlight has recently shone on plant-based for sports performance, ably assisted by the ‘Gamechangers’ program, promoting the virtues of plant-based nutrition for performance, but which also has been widely criticised for its erroneous scientific claims.

A vegan approach to nutrition involves elimination of all animal foods including meat, poultry, fish and seafood, dairy, eggs and honey, and includes wholegrains, fruits, vegetables, nuts/seeds, legumes and products manufactured from these.  A well-balanced vegan diet can provide the wide range of nutrients required for human health and performance, but without significant effort and planning, athletes may find themselves falling short on nutrients, with a subsequent impact on performance outcomes. 

Benefits of a vegan diet for athletes

-        Adequate fibre, vitamin and mineral intake when well balanced (supplementation required)

-        Weight loss (but sometimes gain)

-        Energy levels

-        Provides carbohydrate for high-intensity fuel

-        Digestive health

Potential concerns of a vegan diet

-        Nutritional inadequacies eg. Vitamin B12, Iron, Calcium, Omega-3

-        Restrictive eating patterns

-        Over consumption of specialised vegan processed foods

-        Protein quality and quantity (you have to plan well)

-   Supplement use vs natural food sources

What is keto?

Keto, ketogenic, low-carb/high-fat (LCHF) - however you label it, this style of eating promotes the use of fat as a fuel, along with ketone production (which can also be used as a fuel).  Carbohydrate is restricted to less than 20g/day, with moderate protein (not high) and unlimited amounts of dietary fat, usually with no prescription as to the type or source. 

What does this look like? Plenty of high fat foods like meats and poultry, cheese, cream, eggs, butter, oils, nuts and seeds, while cutting out all wholegrains, fruit, legumes, many vegetables and most dairy, as well as many processed foods.  Not much flexibility in this type of approach, especially if ketosis is the goal.  The modified versions of LCHF allow some carbohydrate flexibility, but on the whole, restriction is the name of the game to achieve the proposed benefits. 

The keto approach has gained much interest in the strength training world for it’s potential to support body composition goals, and in ultra-endurance ranks for increasing the ability to use fat stores as an effective fuel source for prolonged steady-state exercise.

Anecdotal evidence for a positive effect on performance is widespread, however hard evidence from the scientific world is lacking with regard to the impact of keto on high-intensity performance. Some studies indicate a potential risk of impaired performance when high intensity effort is required.

Benefits of keto for athletes:

-       Weight loss (for some people, not all)

-       Improved gastrointestinal symptoms (for some, particularly if existing intolerances)

-       Improved blood glucose levels

- High quality protein

-       Less processed, more natural foods

-       Improved use of fat as a fuel - this does not necessarily = improved performance

Potential keto concerns

-        Inadequate intake of specific nutrients, particularly those found in wholegrains, fruit, starchy vegetables and legumes

-        Gut health

- Excessive meat intake

-        Low energy levels (for some)

-        Impact on brain function, concentration (for some)

-        Restrictive and difficult to stick to

- Impact on an individual’s relationship with food and enjoyment of food

- Negative impact on sports where high-intensity effort required

- Impaired ability to use carbohydrate as a fuel when needed

- Potential impact on dietary nitrate conversion

Vegan keto combo

Yes, it’s a thing, but to be honest I wouldn’t bother.  Many of the vegan sources of protein also contain carbohydrate – so to get nutritional variety and keep carbohydrate at a keto level, it would be challenging to meet overall nutrition needs.  Let’s just say you would likely be eating a bunch of tofu and olive oil and very likely missing out on important minerals. I have not done the modelling for this though - perhaps a good project if anyone is keen to look into this further, or let me know if there are existing resources on this.

Vegan vs keto for performance

The issue with vegan vs keto for sports performance is that there are potential downsides to both. 

A vegan approach provides plant-based nutrient diversity and associated benefits, but without precision planning can result in poor nutrition intake and protein balance. But usually plenty of carbs!

Keto is an approach that seems to be growing in popularity, but the evidence to support its effectiveness for high-intensity performance is lacking at present.  Keto has been shown to enhance fat oxidation in athletes, but this has not consistently translated to performance effects.  If you are an ultra-endurance athlete, where steady state exercise is your thing and you are less likely to need high-intensity bursts, then the ability to burn more fat may be pretty handy.  But if you are a team sport contributor, and need to use your speed and agility to get to a pass or defend a goal, then carbs are the best fuel to help you get there.  Keto might just not cut it.

Part-time keto?

Some athletes will turn to a keto, or lower carbohydrate, style of eating during specific times of the year or training phases - for example early in pre-season when aerobic fitness may be a priority, along with reducing body fat levels. As training intensity steps up, carbs can be re-introduced and timed appropriately around training sessions and to suit training goals. If you need to train hard, carbs are critical.  So is protein, for recovery - and this is where vegan nutrition can let you down if not well planned. But a vegan diet also can allow carb cycling and adjusting according to training sessions, periodisation and performance goals, which keto can’t.

What if you could take the best bits of both approaches to really super-charge your performance?

So which is best?

Although both vegan and keto camps claim to be superior to any other way of eating, neither are the definitive diet to achieve improved performance for every athlete.

Either approach can play a role for specific types of athletes at specific times – with the right preparation and planning.  However you can achieve many health and performance benefits without having to follow any particular ‘labelled’ regime.  In fact the best way to perform at your best is to tailor your nutrition to your unique needs. Sports dietitians work with individual athletes to help them work out the best approach, at the best time, for their individual training and performance goals, considering their philosophical, physiological, psychological and taste needs.

The best strategy for you should include foods that you love, tailored to you, so you can live and perform at your best.

For more sports nutrition updates and tips, you can find me on Instagram, Facebook and LinkedIn.

Effect of LCHF on blood test results PLUS ketogenic diets PLUS coconut oil

I have been thinking about this whole LCHF movement and some of the passionate advocates of this style of eating, and I continue to be bewildered as to why they are SO passionate about spreading the LCHF word?  Perhaps their own personal experience has been so overwhelmingly powerful that they feel no option but to help others to experience the same?  Or is it to challenge the exisiting dietary guidelines and advocate for change (not that too many people actually follow the current dietary guidelines anyway)?  Or is it to promote the next diet book they have at the publishers, just about ready to hit the shelves.  You know what, I am really not sure, and there are probably different incentives depending on the individual.  The wide range of characters promoting LCHF makes things even more confusing – some scientists, doctors and dietitians are gunning for it, and so too celebrities, chefs, and everyday Australians.  Interestingly, Australia is the number one country at present where the LCHF message seems to be getting air time.  Apparently in the US and other countries, there is no such interest, and LCHF may just be viewed as another fad diet.  Jimmy Moore, a speaker at LC Downunder seminars is from the US and he was congratulating Australia on their interest and uptake of LCHF (and for supporting his livelihood via purchasing his books and other resources).  So are we just all being sucked in, when other countries don’t seem to give two hoots about LCHF, or are followers on the crest of the next wave of nutrition truth……..

My curiosity about why LCHF supporters are so passionate extends to Associate Professor Ken Sikaris. His name may sound familiar to you if you live in Victoria and received a blood test report in the last ten years or so - his name may have been printed at the top of each page.  Ken Sikaris is a pathologist, specialty biochemistry, with a particular interest in cholesterol.  A/Prof Sikaris has an impressive resume in the world of pathology.  I hope I am not being naïve, but his apparent neutrality in the commercial world (unless he has plans to release his own brand of coconut oil/fat/paste/milk/cream*see end of post), along with his vast professional experience in pathology, makes it difficult to predict any reason why he would want to be talking about LCHF at the Low Carb Downunder seminar, other than because the research is indicating something.  A/Prof Sikaris has also tried LCHF himself and he credits this for his personal weight loss and improvements in blood lipid profile, which he presented as one of a number of case studies.  He also showed some real research, a pleasant change from the heavily weighted anecdotal and case study format of most of the seminar sessions.  Admittedly, I have not critiqued every study that was presented, but the trends that were observed in the large number of studies he discussed shone quite a positive light on LCHF for cholesterol, triglyceride and blood glucose levels.

I don’t want to simplify the complexities of blood testing and interpretation, but to summarise the content and research within the presentation, the trends observed in blood parameter changes with LCHF from the studies presented are something along the lines of this:

- Increase in Total Cholesterol

- Increase in LDL cholesterol (‘bad’ cholesterol)

- Increase in HDL cholesterol (‘good’ cholesterol)

- Decrease in small dense LDL (‘bad’ cholesterol)

- Decrease in triglycerides

- Decrease in HbA1C

• Please note, these are observed trends that were presented based on studies during one session of the Low Carb Downunder conference and are not indicative of expected changes in ALL individuals.  For some people, a LCHF diet may produce unfavourable results which may be of significant risk to health.

Reading through the list above, the first impression is that eating more fat through LCHF will increase total and LDL cholesterol. Higher fat intake is likely to increase total, LDL and HDL cholesterol, but reducing carbohydrate helps to reduce triglycerides, which A/Prof indicated may be the key element in reducing cardiovascular risk.  He indicated that as triglyceride levels increase >1.5mmol/L, more LDL will be in small dense (modified) form, that hangs around in the blood, rejected by the liver and may end up in blood vessels.  On the other hand, if triglycerides are <1.5mmol/L, LDL are likely to be in the larger form that may be taken up by the liver.  It may be that small dense LDL could potentially be the new marker of CVD risk, and that even if total and LDL cholesterol are higher, CVD risk could be reduced if small dense LDL% is lower.  And this could all link back to carbohydrate and their impact on TG's.  On a low-fat, higher carbohydrate intake, it was observed that more small dense LDL is formed. It was suggested that a short period time of only 3 weeks could potentially show blood changes of decreased triglycerides and small dense LDL.

With regard to HDL, observed increases have been quite large in magnitude, and it was suggested that there is no drug that can increase HDL to that extent. 

HOWEVER, it was acknowledged that not ALL individuals experience positive changes to blood cholesterol profile with LCHF.  For some people, LCHF increases total cholesterol excessively, and this is likely related to genetics.  This is often due to an increase in Lp(a), a modified LDL particle that the liver does not particularly like and so, like the small dense LDL, it can end up in the blood vessels, which can be dangerous for cardiovascular health.

So to summarise the presentation by Ken Sikaris, LCHF can have a positive effect on blood lipid profile, but can have a negative effect in some people.  The dilemma for me is how do you know who will have the favourable outcome and which individuals should be wary. 

During the Q&A panel session, the question was asked if LCHF would be suitable for someone after a stroke or heart attack.  The overwhelming response from the panel was yes, it would be a better dietary strategy for future health, but how do they know how that person will respond to LCHF.  Can a favourable outcome be guaranteed??

The other question is whether the change in blood results is due more to the actual change in macronutrient intake, or related to the associated loss of weight?

During the panel discussion it was also suggested that individuals may be better to go very low carbohydrate to start with, rather than easing into it, to achiever results sooner and allow the body to fat adapt.  Many of the blood parameter changes in the studies presented were based on very low carbohydrate intakes of <40g/day, or what would be considered a ketogenic diet.  The word 'ketogenic' sounds very clinical and a little bit daunting, but is basically the lowest carbohydrate form of LCHF, where ketones and fat replace carbohydrate as fuel.

Jimmy Moore calls ketones 'super fuel', but indicates that you need to keto adapt to become a ketone burner.  I am sure there are a variety of approaches, but his recommendation is to start eating unlimited fat to become fat adapted, then decrease intake over time so it allows stored fat to be broken down for energy.  So it is not a matter of eating as much fat as you like, effectively there calorie control.  With regard to carbohydrate, 30-80g seems to be deemed acceptable for 'keto', and protein is recommended not to be overdone, in case it is converted to glucose (there was lots of talk about gluconeogenesis), which may impair ketogenesis.  Of course, you need to buy a ketone monitor to carefully track ketone levels.  After about 1-4 months you become keto-adapted, and on your way to health and happiness by all accounts.

Many dietitians have scoffed at LCHF as just another fad.  But how many dietitians recommended VLCD programs like Optifast?  I know I do, not routinely but for individuals where it is deemed appropriate.  These programs create ketosis, and can be very successful for weight loss, but they are not for everyone and are not representative of longer term healthy eating patterns.  Is there a difference between VLCD programs and LCHF diet??  There are many, the most obvious being that Optifast for example is designed for a short period of time, not forever.  There are a lot of things to consider when making decisions about the best approach to food and nutrition for any one individual.

It seems that nutrition is becoming more and more complex when really in a practical sense when it comes to food choices we should be getting back to the basics of simple, fresh, delicious food.  The foods you choose are up to you, and based on a range of factors that are unique to you.  If you are finding your nutrition a challenge, speak with a dietitian who can help you work through it.  (although some dietitians may not recommend eating coconut oil by the spoonful as an afternoon snack, see below....)

* Just as a side note from earlier in this post, I really don’t get the coconut oil thing, nor do I understand the current interest and obsession with all things coconut.  Why is coconut oil considered so much better than any other fat?  It’s basically just saturated fat, although it does contain significant amounts of medium chain triglycerides (MCT's) with about 50% of the MCT's being lauric acid, which has been reported to have health benefits.  Coconut oil is great to cook with and adds flavour to foods, but the evidence that it does a lot more is currently lacking.  I heard Professor Andrew Sinclair, Chair in Nutrition Science from the School of Medicine at Deakin University, speak at a recent nutrition seminar in Melbourne, the topic being his area of expertise – fats.  He didn’t have anything particularly groundbreaking to say about coconut fat, but did mention that researchers at Deakin are looking into reviewing the literature on coconut oil and health…..perhaps they will find something exciting, until then.....

This Thoughts post provides informational content only, and is not for individual nutrition prescription purposes.  For more specific nutrition guidance and recommendations tailored to your individual needs you should speak to an Accredited Practising Dietitian.