From Ergo Log
Many dieticians advise clients who are following a low-calorie diet to take it easy on pre-selected days and to eat whatever they want on those days. This makes it easier to stick to a weight-loss diet the reasoning goes. This calorie-shifting approach does indeed work well, nutritionists at Shahid Beheshti University of Medical Sciences in Iran discovered. This is not so much because it makes it easier to stick to a calorie shifting diet, but because the results achieved don’t disappear so fast when you start to eat normally again.
The researchers did trials with two groups each of 37 women with a BMI of 25-37. The women were aged between 26 and 50.
One group followed a traditional – but strict – calorie restriction diet for 6 weeks. The women reduced their caloric intake to 55 percent of their resting metabolic rate. The resting metabolic rate is the amount of calories you burn while at rest.
The other group followed an even stricter calorie shifting diet, which consisted of 3 cycles of 2 weeks. The first part of the cycle took 11 days, during which the women ate only 45 percent of the amount of calories their body burned when resting. The second part of the cycle lasted 3 days, during which the women could eat as much as they wanted.
At the end of the 6 weeks the researchers put the women on another diet for 4 weeks in which they were given exactly enough calories to maintain their new body weight.
The women in both groups lost the same amount of kilograms. But after they had completed their weight-loss diets, the bodyweight of the women in the calorie restriction diet group [CR] increased more than did the bodyweight of the women in the calorie shifting diet group [CS].
The effect is even more dramatic if you look at the fat mass. After coming off a slimming diet the traditional calorie restriction diet group gained fat mass again fast, but the calorie shifting diet group did not.
The women who lost weight on the calorie restriction diet started to burn fewer calories while at rest, whereas the resting metabolic rate of the women in the calorie shifting diet group remained constant.
“The effect of the calorie shifting diet on weight loss was more persistent than that of the calorie restriction diet, while both groups had a 1 month follow-up period with approximately the same calorie intake”, the researchers write in summary. “Further analysis suggested the involvement of reduced resting metabolic rate in weight regain of the calorie restriction diet subjects during the follow-up period, which remained in levels near baseline for the calorie shifting diet subjects.”
The researchers were very strict with their subjects. The amount of calorie restriction was high, and even higher in the calorie shifting diet. If you are following a far less strict weight loss diet it might be that the calorie shifting approach may not work. Why that is you can read here.
Int J Prev Med. 2014 Apr;5(4):447-56.