Intermittent Fasting (IF) is not a brand new concept to dieting, but its popularity has boomed over recent years. With all the talk on internet forums, is it a good method for fat loss? Is it good for maintaining muscle? What about adequate nutrition, especially micronutrients? Do people feel they have sufficient energy? Let’s have a very brief look…
There are different strategies, but the basis of IF is alternating intervals of fasting and times when you are allowed to eat, which intermittent fasters call ‘feeding windows’. The aim is to keep calorie restriction easy. Some strategies have fasts of 16-24 hours, though these are less popular with bodybuilders and fitness fanatics. Others have fasts of just 8-16 hours which are more common. In fact, let’s be honest, most of us actually already have 8 hour fasts: overnight while we’re sleeping, so there’s nothing new there. With IF the fast time is simply prolonged and the individual won’t eat until the afternoon or maybe even later.
The reason that IF is effective in losing weight is that during the fasting you are burning your reserves, primarily fat. However, what some people fail to acknowledge is that metabolic pathways dictate that you will be burning some muscle tissue concurrently after a few hours. This is why IF is not ideal for those looking to gain lean muscle.
During fasting the metabolic rate does slow down, so the rate of fat burning will reduce as the fasting period progresses. However, one of the key concepts in IF is that during the feeding windows a significant amount of food is consumed which speeds the metabolism and the faster metabolic rate continues well into the fasting period. Whether the net effect on the basal (resting) metabolic rate (BMR) is changed is still unsubstantiated by credible research.
The fact that eating is restricted to the feeding window periods means that the total number of calories consumed is fewer than what you’d normally consume – even though it might not feel like it at the time as the amount consumed during these periods may be considerable.
Advocates of IF suggest that you don’t have to eat that ‘clean’ (in the bodybuilding sense of the word) in order to lose weight; but consuming a load of junk food in the feeding window is definitely not recommended. Like any nutrition strategy the Healthy Eating Guidelines should be adhered to; i.e. low sugar, high fibre, low fat, adequate amounts of good fats, plenty of fruit and veg, low salt, etc. This is very important and you must still include your ‘5 a day’ fruit and veg and consume a varied diet to help ensure good nutrition and adequate amounts of all micronutrients.
Definitely do not perform any exercise regimen at the end of a fast as you’ll struggle. Remember, maximum performance will reap maximum benefits from exercise, so always have good pre- and post-workout nutrition.
If you’re a bodybuilder looking to gain lean muscle then Intermittent fasting is not for you (take a look at our losing fat and gaining muscle article for that – includes a meal plan). However, maybe it would suit someone looking to lose body fat and improve their shape with less of an effect on their social life and life in general (you don’t have to be preparing 6 meals a day). Some people have made the move into an IF regimen and find it suits their lifestyle better as it’s more convenient; these people have found they stay leaner than before.
Some intermittent fasters report it as a lifestyle change rather than a temporary diet. However, some people have tried the regimen and can’t get used to the fasting period, reporting feeling hungry, light headed and dizzy; indeed, some people find it is not convenient for their lifestyle as, during the feeding windows, they are unable to consume enough food as their appetite doesn’t allow it.
Good research on intermittent fasting is scarce as the dietary regimen is a relatively new concept. However, I think this strategy is here to stay around for a while and we will be seeing another Atkins Diet; this is because it is convenient and relatively easy and it is reaping the most fundamental of all results: fat loss.
Is IF healthy? Well, it’s certainly not as healthy as eating small regular meals and the key to its success is the fact that followers do lose weight and do seem to retain muscle. However, IF isn’t for those wishing to increase their muscle and strength.