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  • Jonny

Is Intermittent Fasting Good? - Nutrition Series

A lot of you have probably already heard of intermittent fasting and may even be considering it as a way to lose weight in the new year, but you should be asking yourself – as with any diet you’re considering – is it healthy, does it work and is it compatible with a vegan diet?


I would firstly like to say, both Jenny and I advocate a whole foods, plant based diet with calorie restrictions as the healthiest, most sustainable way to lose weight. In our opinion, eating a calorie measured whole food plant based diet means you become more attuned with how much you should be eating on a daily basis.

That being said, we know some of you prefer a strict regime type diet, as your self control is more an all or nothing type thing, hence why we decided to write about intermittent fasting (IF).


As we speak, my brother is currently doing intermittent fasting on a predominantly plant-based diet, and my colleague is also doing intermittent fasting. All it takes it to look in a couple of Facebook groups and you’ll see an influx of people recommending IF as a great way to lose weight.


So what is IF?


The idea is, as the name suggests, fasting for intermittent periods of time. There’re varied time frames when you can eat in, but I think the most common version of IF is usually between the hours of 1pm and 8pm when you can eat food, and the rest of the time you fast. That being said, my brother is doing a much more extreme version where he can only eat between 6pm and 8pm! There’s little restriction on the kinds of foods you can eat in that “eating period”.


Psychologically, this works for some people. Due to the strict time periods they can eat in, they are able to do their all or nothing approach. The idea is that because they have a shorter window to eat in, they end up not eating as much – therefore start losing weight. There stomach also tends to shrink which means during the eating window, you start to eat less because you become fuller quicker.


Is it healthy?


This really depends on how you do it. As there isn’t much restriction on what you eat during the eating period – you could either eat a load of healthy whole foods, lots of veg etc and it will be relatively healthy. Or you could end up bingeing on ice cream, crisps and burgers because you’re telling yourself it’s fine as its within the food window, so you’re still sticking to your diet. The latter example is clearly very unhealthy and you probably won’t even lose any weight doing it!


The other potential to make it unhealthy is that you may not be eating enough. If you are choosing a very strict time period when you can eat, you may end up only getting a few hundred calories a day- with nowhere near enough nutrients and minerals! Again, this is clearly not healthy. If, however, you are still ensuring you’re getting enough calories and nutrients to be healthy but a small calorie deficit to still lose weight then there’s likely little issue with it. So long as you’ve got quite a long eating window.


It should be taken with caution by anyone with medical issues. By fasting, this could cause your blood sugar to fluctuate and go really low during the fasting periods. Obviously - as any diabetics out there will know – this can be potentially fatal for some people. When starting a new diet, you should always check with your doctor first to ensure there won’t be any complications.


It would also be a problem for people who need to take medications with food three times a day. With some medications it’s vitally important to be taken with food, so if you’re fasting you won’t be able to take the medicine at the appropriate time – obviously potentially causing serious problems. So, I repeat, check with your doctor first.


Is it good for exercise?


It’s not ideal. When you are exercising a lot, you want to making sure you’re supplying your body with the required proteins, fats, carbs and calories at the right times. Your body is constantly repairing when you exercise, and so giving it as steady as possible supply of the nutrients will optimise recovery.


Also, if you try to exercise after not eating for 15 hours or so, you will find your energy levels are down to critical levels! You’re not gonna have as much energy to smash the workout. This is especially so for people doing endurance training. You really want to have stocked up on carbs a few hours before going for a long run for example.


Is it compatible with a vegan diet?


Yes. In the diet plan, as I said, it doesn’t detail what you should be eating, simply when. So actually to make it a healthier diet, you should be eating whole plant foods (whole grains, vegetables, beans etc). However, as I said above, you should be making sure you’re getting enough food within the time window. Because whole plant foods tend to be low in calories, due to only being able to eat during a certain time period you could end up having too much of a calorie deficit when doing IF which isn’t good for your body, nor is it sustainable. You only want a small calorie deficit, so it’s still worth logging what you’re eating to ensure you’re eating enough.


So would I recommend it?


Personally, no. I still think the much healthier thing to do is be disciplined in your diet. Ensure you’re only putting healthy nutritious foods into your body, then the eating window to do it in doesn’t really matter so much. I also think when you’ve got exercise goals, its counterintuitive to fast. This is just my opinion though.


If you are dead set on doing it though, in summary to make it as healthy as possible, you should count the calories, macros and micro-nutrients to ensure you’re still fuelling your body with enough nutrients. You should also be less restrictive on the time window and focus on only eating healthy foods during the non-fasting periods. If you are going to do it, good luck – but please make sure you check with your doctor and make sure you do it as healthily as possible!