Disclaimer: Don’t make any major changes to your diet based on what you read on the internet. Always consult a qualified dietitian or your GP first, especially if you have any underlying health conditions. I am just sharing my experience, make of it what you will!
Despite running roughly 50 miles per week consistently for the last few years, I’ve always had a bit of a tendency to put on weight easily. There might be a genetic factor to that but more likely it’s due to being weak-willed when there is food available. No matter how much I tried (and succeeded) to shed a few kilos, along would come a birthday, Christmas or other occasion and those few kilos would jump straight back on. Coming home from Christmas and New Year 2024, I weighed in at 80.9kg on the 3rd January, heavier than I had been since 2021. With a big year of races coming up, I decided it was time to do something about it!
Along with the books on running psychology that I reviewed last month, the other book on my Christmas list was Christopher McDougall’s “Born To Run 2”. While his original book promoted the benefits of barefoot and minimalist running, the sequel looks at the diet of the Tarahumara (the Mexican ‘tribe of ultra runners’) and the benefits it can have. Put simply – they follow a low-GI diet – so I decided to try it!
What is a low GI diet?
All foods can be categorised according to the Glycemic Index (GI). Essentially what it measures is how easily the food can be broken down into glucose, which is carried around in your bloodstream and metabolised as the primary source of energy for everything that you need to do… not just running!
Foods with a high GI can be turned very easily and quickly into glucose. Examples are obviously sugary foods – sweets, cakes, syrup – but also refined (white) flour which means most bread products and pasta, as well as potatos (chips, crisps…), white rice, and (sadly) beer. As you probably know, many foods also have a lot of added hidden sugar, including a lot of “healthy” breakfast options such as muesli and granola.
Foods with a low GI are the opposite, they take longer for the body to break down into glucose, either because they contain more complex molecules or significant amounts of fibre which slows down the digestion process. Examples are nuts, beans, meat and fish, diary (cheese, milk, cream…), many fruits and vegetables, and whole grains (oats, brown rice, barley…).
It’s a sliding scale and there are lots of food somewhere in the middle. You can find plenty of lists to look up individual foods if you’re unsure.
The problem is that our normal Western diet is mainly full of high GI foods. When we eat them we get a rapid increase or spike in our blood glucose levels. The body responds to this by releasing insulin, which triggers the storage of any excess glucose that’s not immediately required for exercise or recovery as body fat. This causes the blood glucose levels to drop rapidly, making us hungry for more food and starting the cycle again. Since most of us start the day with a sweet breakfast (cereal, toast with jam etc.) we can end up riding the spike/crash rollercoaster all day long. By replacing high GI foods with low GI alternatives, it smoothes out the peaks and troughs in our blood glucose level, reducing the opportunity for our bodies to store fat and feeling full for longer. At least that’s the theory!
What a low GI diet isn’t – it’s not about calorie reduction. You can still keep a healthy overall amount of calorie intake which is particularly important if you have a high training load and are exercising frequently. Going into calorie deficit can cause your overall fitness to suffer and in the worst case lead to conditions like RED-S. Low GI is also not a low-carb diet (like the Keto diet), although it has some similarities. There are plenty of carb options that are low GI, so you can continue to eat a balanced, healthy diet. It’s also perfectly possible to follow a low GI diet while being vegetarian or vegan if that’s your thing.
How to start a low GI diet?
Born to Run 2 has a detailed plan for switching onto a low GI diet, but essentially it involves being very strict for a period of roughly two weeks to force your metabolism to adapt. This is probably the hardest part of the process as it requires cutting out some common foods entirely (no potatoes or white flour products). To avoid having to cook several different meals Julie and I went through this together in January. It’s a bit of a “cold turkey” phase and we definitely felt a bit rough for a few days – Julie worse than me. We both experienced the “keto headaches”, which were not pleasant… but we got through it. After the two week period is over, you can re-introduce a few more medium and high GI foods, or stick firmly to the low GI diet as you prefer. Obviously the more you stick to it the bigger the benefits!
Here’s an example of some of the changes I’ve made that I’ve stuck to for the long term:
- Breakfast – swapped muesli for either smoked mackerel on wholewheat toast or porridge with nuts and dried fruit.
- Cut out white bread – lunch is usually salad or fruit with oatcakes and cheese (if not leftovers from the night before)!
- Cut out pasta and white rice – brown rice is an acceptable option to everyone (even the kids), and if we’re having pasta we usually cook a portion of an alternative (wholegrain, pea, lentil) for me.
- Swap potatoes and chips for sweet potato. Usually I’ll have a bigger portion of veg with dinner and less potatoes.
- Sweet snacks (evening chocolate bars 🙈) replaced with savoury – cheese cubes, nuts and dried fruit. If you really want chocolate, dark is the way to go as it has much less sugar.
- Low GI first – if you have to eat something high GI, then make sure you eat some low GI foods first, to slow down the overall rate of digestion and avoid a glucose spike.
All of these are fairly easy to introduce, even alongside cooking “normal” meals for the rest of the family. The main thing which required a bit of experimentation to find a good subsitute was a pizza base. I’ve shared a good recipe at the end of this post.
The results
After the first few days which were a challenge(!) I’ve felt great throughout the whole last three months. I’ve gone through a whole training block, including speed work, hill runs and long runs, not to mention an epic race at Rasselbock BYU. I’ve been sleeping well, injury free and have plenty of energy for training. I’ve lost weight consistently, between 0.5 and 1kg per week on average. The only weeks where it’s been harder has been two weeks I was travelling with work,where eating in restaurants makes it more of a challenge, and it showed 😬 Can you spot those weeks on the graph? In the end I finally hit 69.9kg on 27th March, a little less than 3 months since I started!
I think besides the physiological benefits that result in less fat storage, there are a couple of less obvious ways that the low GI diet helps. Firstly, most of the things that I would typically snack on fall into the high GI category. While I did allow some evening snacking, especially to get a bit of protein in immediately after a run, most of the time I didn’t feel as hungry between meals and if I did have the urge to snack I didn’t have anything in the cupboard I was allowed to eat… so much less snacking overall. Also I completely cut out beer, which is high GI. The second trick (not strictly related to low GI) is portion control – basically I switched to eating meals off a smaller plate! Training my body to obtain more fuel from fat stores rather than high levels of blood glucose meant I could eat a little bit less, lose body fat and still have plenty of energy for training!
At the start of March I ran (and won) the Rasselbock BYU, whereI largely stuck to my normal race diet including carb loading with (high GI) Domino’s pizza the night before and the usual mix of real foods, energy gels and drinks throughout the race. It’s fine to have plenty of glucose flowing round your system when you’re burning it off! After the race I switched back to low GI foods again with no ill effects, recovered fine and my weight continued to drop.
As I said at the start, please do your own research and consult a qualified professional before making changes to your diet. Having said that, this really worked well for me and my nutrition advisor said that a low GI diet is generally regarded as suitable and healthy for all, and simply reverses the increase in ultra-processed, added-sugar foods that are common in our diets. If you do try out any of the suggestions in this post, please let me know by posting a comment or connecting via our socials – I’d love to know how you get on!
Gram flour pizza base
Some foods required a bit more experimentation to find a suitable substitute, and one of those which was non-negotiable was Saturday night pizza. After a few failed attempts, I am now using the recipe below. It’s super-easy and requires only a few minutes to prepare. It’s also gluten free, dairy free and vegan!
The ingredients (per 1 pizza base):
- 115g gram flour (a.k.a. chick pea flour, available in most major supermarkets or a local Asian store)
- 160ml water
- Pinch of salt
- Tablespoon of vegetable oil
Method:
- Mix all the ingredients (apart from the vegetable oil) together in a bowl to make a runny batter. You can use an electric mixer or a whisk.
- Leave to stand for 30 mins (or longer if possible).
- Heat the oil in a large frying pan, skillet or griddle pan to a high heat. Give the batter a final whisk to get some air into it.
- Pour the batter into the pan, tilting the pan to ensure an even spread right up to the edges.
- Cook on one side for approximately 2 minutes, until the batter is dry on top.
- Using a spatula, flip the batter over and cook for a further 1 minute.
- Remove from the pan and place on a baking tray.
- Top with tomato puree, your favourite pizza toppings, and plenty of cheese.
- Bake for a further 10 minutes in a hot oven (200-220C)
- Enjoy a low GI treat!
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