Nutrition trends and current evidence with Danny Lennon | EP#208
Danny Lennon, founder of Sigma Nutrition Radio makes a living staying up to date with current research and evidence in nutrition. He discusses current nutrition trends and what the consensus of them actually is.
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In this Episode you'll learn about:
Carbohydrates and low-carb diets
The gut microbiome
Intermittent fasting and time-restricted feeding
Genetics, genetic testing and nutrition
- Endurance sports nutrition: state of the art in 2019 with prof. John Hawley | EP#181 on That Triathlon Show
- All nutrition-related episodes - on That Triathlon Show
About Danny Lennon
- I have a Masters degree in Nutritional Sciences and an undergraduate degree in Biology and Physics
- For the past 6 years I have a company called Sigma Nutrition. Our goal is to put out educational media around evidence based nutrition and other subjects like sleep and performance.
- We look at the intersection between performance and health. The main lense we do that through is nutrition. We have the podcast Sigma Nutrition Radio but we also give content on the website of Sigma Nutrition.
- We also have a coaching aspect. Four coaches look after a variety of clients with many of them being athletes (MMA, boxing, taekwondo, power lifting).
What are the hot topics around nutrition in the academic world?
- A lot comes down to what a person thinks is interesting. I have a deep interest in circadian biology. Important things as sleep and exposure to light, chrono nutrition (meal timing and distribution of calories accross the day) which have impacts on our circadian biology.
- The circadian rhythm is about 24 hours a day. This rhythm can be influenced by certains things in our environment, with the main one being light and dark.
- Get sunlight early in the day and avoid lots of bright light late at night. This last one can have lots of influences on the circadian biology.
- From a nutritional standpoint I look at how nutrition intake can have a role on our circadian rhythm and how that rhythm may have implications on when we should eat certain foods. For example, more carbohydrate intake early in the day.
- Another example which is exciting is the area of the gut microbiome and how environmental factors can influence this. And how the gut microbiome can influence other processes in the body.
- This is a very new field and has a lot of complexity. It still needs a lot of research to make conclusions.
- An example of this is research of the interaction between the gut and the brain and potentially how the microbiome can influence certain processes in that gut-brain axis.
- The research is looking into the influences this has on, for example anxiety, depression, altered mood states, and how changing the microbiome can have an influence on this.
- On the practical side it seems that a high degree of diversity of bacteria within the microbiome is a good thing. In terms of an optimal or ideal gut microbiome we can't say what that is at the moment, and maybe this will never be possible. It can be more related to the context of an individual person.
- For example the microbiome can change dynamically and in a short period of time by changing your diet.
- Saying that you need to take in certain probiotics, probiotics in general, or eating specific food is still too early to say.
- The big take home is: eat plenty of variety of vegetables and eat enough soluble fiber. Then you are probably doing your gut some good service.
Other trends in the applied fields among nutritioners
- There is no shortage of coaches, dietitians, nutrioniisits and athletes trying different types of diets.
- The ketogenic diet is very popular in the last years.
- Intermittent fasting and time-restricted feeding are also popular.
Carbs and low-carb diets
- With athlete and conventional sports nutrition we've known a long time about the benefits for sports performance of carbohydrates.
- Conventionally the statement was if you are an athlete with a high workload you need a high carbohydrate diet. Most of the literature would have backed that up.
- In recent years, more is published about whether we can have a benefit of altering low/medium/high carb intakes on certain days - "carb cycling" or carbohydrate periodisation.
- Nearly all sports benefit of having full glycogen stores and exogenous glycogen and carbs for performing at full potential.
- With endurance sports there may be exceptions. For example, for Ironman or other ultra endurance events.
- The other sports will need glucose oxidation to perform at your best as the intensities and speeds are higher. This includes e.g. the marathon.
- On the flipside, we see beneficial adaptations in the body when people go through periods with lower intake of carbs. With carbohydrate restriction there are adaptations as increased gene expressions, increased production of mitochondria and athletes being able to train at higher intensities with more fat oxidation. So we see potential benefits but we can't get that high end performance at high intensities.
- A potential way to look at it is by using certain sessions where we take in less carbs and more carbs for the training sessions with lots of quality work or high intensities.
Overview from the perspective of endurance athletes on carbohydrates in general and low carb intake
- The key thing to take away is that by restricting carbs or through continuous low carb intake there are some adaptations that might be beneficial as mentioned earlier.
- However, there is no evidence for improvement in performance. There will still be intensities where you will need glucose or carbs oxidation to have the highest input. Without carbs and relying on fat oxidation you won't be able to produce energy quick enough. You will pull down the intensity.
- People say that with a low carbohydrate diet or a ketogenic diet you have less glycogen breakdown. On the surface that seems a beneficial thing as you may not run out of glycogen as easily. But as it seems, after even 5 days of low-carb intake there is a reduction downregulation of the enzyme pyruvate dehydrogenase. This essentially means that even when carbohydrates are refed, the athlete still has a poorer ability to be able to break down glycogen into glucose to use. They have the stored glycogen but can't use it (glycogen impairing). For those reasons it's probably not a good idea to be chronically on a low carb diet.
- Maybe it can work for Ironman and ultra endurance events because of the duration of the event and the low intensity where you can continuously be in fat oxidation. For other endurance events, at a certain moment you will need to rely on carbohydrates.
- If you are on a low carbohydrate diet and at a certain moment you need to take in carbs you'll still have an impaired ability to use those carbs.
- In general, on certain training days you can go low carb; but for times where you want your best performance in training sessions and events you want to be used to having carbohydrates. Shorter, low-intensity sessions can be done without the intake of carbs.
Intermittent fasting and time restricted feeding
- Intermittent fasting and time-restricted feeding have some things in common but are slightly different.
- Time-restricted feeding is about the food intake withing the dark-light cycle. It's about taking food in during the day and avoiding it at night but also trying to avoid eating relatively soon after waking up, continuing throughout the day until late in the evening.
- The goal is to shrink down the food intake window, for example to 8 hours or 10 hours.
- Intermittent fasting has different protocols. For example, a daily intermittent fasting protocol is basically the same as time restricted feeding. Every day there is a shrunken down window of feeding and a longer fasting window.
- Other types of fasting would be a full day of fasting once a week. There is also the 5-2 diet with 2 days a week of fasting where it's allowed to consume only about 500 calories. You also have alternate day fasting where every second day you have a fasting day with around 500 calories. Next to these there's an area of prolonged fasting where you fast for multiple days.
- To conclude what the benefits of fasting are is difficult. We can change how long we fast, the frequency of fasting, and the degree of the restriction. So it's very hard to define one thing as fasting.
- One of the benefits is that people tend to see weight loss as much less calories are being taken in.
- This may or may not have benefits for endurance athletes. Certain training sessions you need to fuel properly. If you start cutting down the calorie intake this can have implications on your session and on your recovery.
- But for certain aspects it could be useful. For example, when being injured or having taken time off and having gained body fat during this period.
- It is important to know that it could limit the ability to get in nutrients when you need them the most. A lot comes down to the context and what the goal is.
- To look at the benefits of fasting scientifically the question is: 'was it the fasting itself or was it the weight loss that caused the effects?' What has been shown in studies is an improvement in blood glucose, but most people also lost weight through the studis, so the blood glucose change could simply be due to weight loss rather than fasting.
- The trials where weight loss doesn't occur showed that time restricted feeding is beneficial for glycemic control or metabolism of certain meals. Carbohydrate and fat metabolism is kind of screwed up late at night so large meals at night is problematic. In the time restricted model the blood glucose is less elevated or doesn't stay elevated that long after the same meal in the morning versus late at night.
- Depending on the fasting protocol and from a longevity perspective it could be beneficial for health.
- The question is: 'Does fasting have benefits above and beyond of what we get from the same foods without fasting, but maintaining the same overall dietary habits?' This question is much more difficult to answer.
- With fasting, general health improvements can be seen over a longer period but we can't say everyone should be fasting. How often and how much to do, that is very difficult to say.
Genetics and nutrition
- This is about how our genes influence the food choices we need to make and how our food choices can potentially influence gene expression.
- A lot of companies offer genetic tests to look at how you should be training or tell you your ideal diet.
- The main consensus is that certain genes interact with nutrition and training. But we can't run a genetic test and tell you what training you should do or what you should eat.
- An example is that we can look at certain genes to see if someone has a slow or fast metabolism for caffeine. Or certain genes can be looked at to see the risk of heart disease on a high fat diet or not.
- On the training side we are certainly not yet ready to say what sport you should do for example.
- We still need to keep an open mind in how people respond to certain meals, how people deal with certain nutrients, what type of enzymes they have that are working or not, the absorption of different nutrients based on that.
- There are differences in how people respond on a caloric surplus or deficit.
- Regarding energy balance and expenditure, some people have a (relatively) massive energy expenditure through non-exercice. But other people fall on the opposite side of the spectrum. So there are some genetic variations here.
How can people get quality information about nutrition?
- Nutrition is one of those topics with so much debate and this makes it very difficult to spot the accuracy of statements.
- I would suggest to avoid red flags such as 'this is the diet to follow'. Be sceptical. Be open to the information but also look at the competing ideas and where are the sources from, look into the research which was mentioned.
- Someone who claims to have all the answers and claims to be 'the expert' is a red flag.
- Also be aware of what could explain the potential emotions of people speaking about a certain subject. Are people speaking from an emotional or a rational standpoint? Are they basing their statements on objective data? It is a process to get skilled at this.
- We need to search for the consensus between scientists and if there is a consensus.
- In my case it is important to have people listening to the podcasts, not to let them believe what I'm telling them but to decide themselves what parts are relevant for them. It's not about being told what to believe.
- What is your favourite book, blog or resource related to endurance sports or your field of expertise?
- What is a personal habit that has helped you achieve success?
- Humility. The one thing I try myself to remind off is how little I know of in live in general. It's a continuous learning process. Being confident of who you are but with humility.
Links, resources and contact
Links and resources mentioned
- Endurance sports nutrition: state of the art in 2019 with prof. John Hawley | EP#181 - on That Triathlon Show
- All nutrition-related episodes - on That Triathlon Show
Connect with Danny Lennon
Connect with host Mikael Eriksson
Hi! I'm your host Mikael,
I am a full-time triathlon coach and an ambitious age-group triathlete. My goal is podium at the Finnish national championships within the next few years.
I first started the website Scientific Triathlon in autumn 2015 as a passion project to share my learnings with a larger triathlon audience. Later on, in early 2017 I started the podcast That Triathlon Show.
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