Does fasting have a weight loss advantage beyond the effect of restricting calories?
The key to weight loss is to create an energy deficit: energy expenditure (e.g. physical activity) needs to be higher than energy intake (e.g. food).
Daily caloric restriction is an effective way to achieve weight loss by creating a negative energy balance. However, some find this type of dieting difficult because calories must be restricted every day.
Some suggest that alternate day fasting is a better option than regular dieting. In alternate fasting, calories are cut down a lot (by 75%) on one day, while you can eat without restriction on the next day. In addition, it’s often claimed that fasting results in beneficial effects on hormones and metabolism.
This study compared the effects of 1-year alternate day fasting on weight loss (and maintenance afterwards) compared to daily caloric restriction. The alternate day fasting group ate one day 25% and the next day 125%, while the daily caloric restriction group ate 75% every day. Macronutrients were matched between the groups and subjects received all meals for the first 3 months of the study.
Alternate day fasting resulted in similar weight loss compared to daily caloric restriction.
In addition, participants in the alternate day fasting group had more difficulties with adhering to the diet.
Therefore, alternate day fasting does not appear superior for weight loss compared to regular dieting, nor is it easier to stick to for most people. However, if you personally like the eating structure, it can be an effective tool to lose weight.
Go tot the next infographic in the dieting series:
Ketogenic diet does not increase fat loss?
This is a really helpful summary thank you! Most people of all ages, male and female, find change hard. Dietary changes to achieve weight loss are no different. Learning how to shop for and prepare appetising meals and snacks that fit with your energy deficit plan (and other dietary goals) is key to success. We know that small consistent changes, repetition and time are required to form new habits.This may partly explain why many find daily energy restriction easier than alternate fasting in the long term. Fasting is not for everyone but can be a great kick start to a weight loss attempt. It can also help people gain confidence that they have control over their eating habits. A range of tools that increase self confidence and self efficacy are important for success.
This is mostly middle age women having trouble with adherence. Also, it’s not clear if it was self-reported on calorie intake.
And finally, this is a particular version of alternate day fasting of still eating on fasted days (?!)
I guess middle aged women might have more difficulty with adherence than others populations. However, that does not change that the fasting diet was harder to adhere to. That is in direct opposition to the claim that fasting makes it easier to hit a caloric deficit.
Yeah this was just one of the many types of fasting diets. But based on the data we have now, it doesn’t look like fasting has a metabolic advantage.