You may or may not have heard about intermittent fasting, but the real question is – does this type of fasting actually help you lose weight?
Intermittent fasting is a diet regime in which a certain period of time of fasting is followed by another time period in which one is allowed to eat certain foods. You may have heard of some of the more famous intermittent fasting regimes, such as the “8-Hour diet”, “Fast diet”, the “Warrior diet” and number of others. They all proclaim that they induce very quick loss of fat, and yet after the fasting period is over one can eat whatever they want.
So, how true are those claims, and doesn’t fasting contradict the common nutritional theory that one should eat small and many meals a day to keep their insulin levels from spiking?
Let’s go back to intermittent fasting. It involves time periods from 12 to 48 hours of fasting, which are followed by 8 to 24 hours of non-fasting. This according to the authors and followers of these diets leads to easy weight loss without the need of caloric deficit, also the loss of more fat rather than muscle as well as an easy method to keep the lower calorie intake and thus increase the weight loss.
So, how much of this is actually true?
First of all, studies of the results of intermittent fasting and other constant calorie limiting diets show that the weight loss is actually the same, and that changing the schedule and timing of meals has no effect on weight loss or the expenditure of energy. In fact there are other studies which have found that long time periods without a meal can actually hinder the loss of weight because of the insulin spike following meals and the reduced thermic effect of food when the meals are irregular.
The other claim that intermittent fasting is not actually a diet because it doesn’t involve calorie control is also not true, because there is no evidence that a person can lose weight when on intermittent fasting without counting calories, or that they will lose more weight than if following a normal calorie deficit regime.
After all, calories are an important factor, and also for permanent results, the weight loss must come from the loss of fat rather than from the muscles of the body, and there is no evidence that this type of eating leads to the loss of more fat and less muscle than a normal diet.
There is no scientific evidence that eating less frequent meals helps reduce the hunger. One study even found that eating a single meal per day increases the hunger levels, and with the increase of hunger comes the increase of irritability and preoccupation with food.
Also, fasting could affect the energy levels and the athletic performance too, so it actually doesn’t have an effect on the calories being burned. Previous studies have found that Muslim athletes generally perform worse during Ramadan, when no eating or drinking is allowed during the day. Of course, the performance and mood of a person during fasting differs in different people.
One thing which is good about the reduction of the daily meal frequency is that this allows for better control over hunger, and gives a better structure to the diet.
Overall, intermittent fasting will cause weight loss, and for those who can strictly follow this type of eating and fasting regime, the results could be quite satisfying.
Unfortunately, because of the side effects from fasting, including: headaches, constant hunger, bad mood and irritability and problems with concentration, few people have the strength and will power to keep up with this type of diet for a longer time.
I was almost caught up in the hype of intermittent fasting then realized the above. I did try it and did not like it.
I first tried skipping breakfast for a few days. The result was: I was tired, irritable, no energy to workout on the same amount of calories as If I would eat normally. I have more energy and less moody etc on same calorie amount spread out over 4 meals a day . I also used to do 6 meals a day for a very long time, I have now found 4 is better for me. They always say don’t do something you can not maintain for life and there is no way anyone can do any form of intermittent fasting for the rest of their lives.
Another reason that some people practice intermittent fasting is the research suggesting that it can function as a caloric restriction mimetic in the sense of improving lifespan and health span at lower, or perhaps zero, actual caloric restriction. It is hypothesized that the resulting lowered average IGF-1, insulin, and blood sugar are major mediators of this effect.
However, since caloric restriction often occurs implicitly with intermittent fasting, it is not totally clear the results are independent of intermittent fasting. I hope to review this literature in the near future to reach a clearer conclusion.
I am on lean gains style of intermittent fasting going on two years and feel great.
I have gained strength and lost fat doing it his way. I totally enjoy my freedom of having two really large meals a day and be done with it. Beats the 8 a day style i had before.
I think intermittent fasting is basically an easily followable set of heuristics that allow for a sustainable calorie deficit. There might also be some partitioning advantage for shifting most of your food to the post workout period.
Smaller meals work way better for me. And you don’t need to feel full after a meal, ever. Calories in calories out, that’s all that matters.