Race Day

24 February 2019

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June 21, 2018 at 1:07 pm

BHM 2019  |  News

Eight truths & myths about sports nutrition

 

There are all sorts of nutrition tips out there – some good, some bad. Helping us to sort us the wheat from the chaff is sports nutritionist Renee McGregor, author of the book Training Food.

  1. Coffee increases fat metabolism and can help you lose weight = myth

“There is some evidence that caffeine – rather than just coffee – can boost your metabolism a little. Is it significant enough to cause a huge amount of weight loss? Probably not. I use it with athletes when we’re looking at performance – there’s a lot of evidence to show that using caffeine in the correct manner and in the correct dose can improve performance because it will affect your perceived effort – so particularly at the end of a race when you’re feeling quite tired. Typically I’ll get people to take a caffeine gel in the final 5k at the end of a marathon or half marathon. It can really help you to feel like you’re not as tired and the effort you’re putting in is slightly easier. But in terms of weight loss, there’s very little evidence to show that the increase is enough.”

  1. Eating late at night will cause you to gain weight = myth

“This is a good old fashioned myth. There’s very little proof behind it and it really depends how sedentary you are. If you’re quite active then eating late won’t do you any harm – you don’t suddenly start storing fat overnight. If you look at the chemistry, overnight is when you’re fasting so that’s generally when you’re breaking down your stores to use for energy and to keep your blood sugar levels constant. The problem really is if you over-consume calories during the day – if you over-consume you’re going to end up putting weight on.”

  1. Chocolate milkshake is great post workout fuel = truth

This is definitely true. Chocolate milk rehydrates, it’s got the right combination of carbs and protein, and it’s also got the right combination of the right types of carbs and protein. After a workout you’re going to need to refuel glycogen stores and repair muscles. You’re going to need an easily digestible carbohydrate and the lactose and sugar from the chocolate does that. And you’ll need an easily digestible protein which you’ll get from the whey in the milk, so it’s a really good choice.”

  1. Haribo or jelly sweets are as good as an energy gel for fuelling during a long run = truth

“You can indeed use jelly sweets in replacement for gels; it’s very much an individual preference on what you like to take during a run. Most energy gels will provide you with 20-30g of carbohydrate, so you’d need about 5 or 6 jelly babies to get the same amount. I tend to use gels because I find them easier – I find it too difficult to chew while I’m running, but my friend prefers to eat a jelly baby every few minutes to keep her going. It’s really just preference.”

  1. A high protein diet can help you to lose weight = truth

“Yes it can. I would never advocate a pure protein diet; I think you definitely need some carbohydrate in there but a high protein diet will help with satiety levels – so keeping you fuller for longer – and also help to maintain lean muscle mass while restricting your energy intake. Often when you restrict your calorie intake you’ll lose lean muscle and fat mass, but the more lean muscle mass you lose, the less metabolically active you are, so by having a high protein diet you’ll maintain your muscle, which means you’ll remain metabolically active and the weight loss will continue.”

  1. Eggs increase blood cholesterol levels = myth

“There used to be a belief that eggs increased your cholesterol level, but actually you make cholesterol within your own body so if you have a very high fat diet and you are prone to high cholesterol, you will make it anyway. Eggs themselves are not contributing to high cholesterol.”

  1. Your body can adapt to fat or protein as its primary energy fuel = truth

“It can and I do help ultra runners with fat adaptation, but we never ever take carbs out entirely; we periodise their intake. So if they’re going to do a track session, they will still have carbs in their diet. Your body will always use carbohydrate preferentially as fuel and it will use it a lot quicker and lot easier so you’ll be able to maintain a higher pace. It’s the fuel you tend to need in a race or high intensity session. But if you’re going out for a long slow run where you’re not worried about the pace, by all means do it fasted or without carbs in your system – so for example rather than eggs on toast you’d have eggs and avocado, or something similar. Eating in this way makes you become better at utilising fat as fuel. We all have huge stores of fat within us, no matter how thin a person is, and we become better at using that fat as fuel. So when you go into a race situation where you are taking on carbs, although you will use carbs as fuel, your body will also be burning a higher percentage of fat than normal because it’s got used to using fat as fuel as well.

“As yet, however, there is no study to prove that a high protein or a high fat diet actually improves performance – they’ve done studies to show that you can use protein and fat as a source of fuel, but there hasn’t been a study so far which has tracked performance. So far, all the scientists have said that periodising your carb intake according to when you need it can help your body to learn to use fat stores for fuel. It can be hard at first for your body to get used to, but your body does adapt.”

  1. Gluten-free foods are healthier = myth

“For some people a gluten-free diet is essential, but others eat gluten-free because they think it’s healthier. But recent studies have found that a gluten-free diet when you don’t need it doesn’t benefit you in any way so there’s really no point in doing it unless you need to. Some people say they feel bloated after a bowl of pasta or bread and they blame it on the gluten, but the thing that most people don’t realise is that for every gram of carbohydrate you have in your body, you tend to store 1-4 grams of fluid as well so you do tend to feel fuller. That doesn’t necessarily mean you’ve got an intolerance to it – it can just mean you’re holding more water, and to a certain degree that’s good because it will make you feel fuller. And if you eliminate anything you don’t need to from your diet, your body will struggle a little when you introduce it in the future.”