In the last few years, there’s been a lot of interest in calorie-restricted diets for weight loss.
These can vary significantly, from intermittent fasting (where you restrict eating to a certain window of the day), alternate day fasting (where you consume limited or no calories on every other day) to the Fast 800 which promotes rapid weight loss by drastically reducing calories with the “Mediterranean diet”.
The basic idea might seem obvious: reduce how much you eat, and you’ll theoretically lose weight.
But are they healthy? And will you just put the weight back on if you stop?
What are calorie-restricted diets?
The amount of energy you need each day varies based on your age, sex, body composition, how physically active you are, and any background health considerations.
Calorie-restricted diets aim to reduce a person’s overall energy (calorie) intake. And in certain instances, when managed carefully by health-care teams, there is evidence for their benefits beyond weight loss, including as an intervention before surgery.
The general aim is to eat less than the body uses, causing the body to draw on its stored energy – fat. Over time, this imbalance, generally using more energy than you eat, can lead to weight loss.
But these diets are not meant to be followed forever. Most involve a period of restricting calories, before transitioning to...