If the calorie restriction, namely reduces your food intake, can be recommended in a strictly medical setting by health professionals, it should under no circumstances be performed alone, alert researchers at the University of North Carolina. Their new study published in the Journal of Bone and Mineral Research affirms that this habit can be harmful to the bones of the people who adopted it while continuing to practice a frequent sports activity. To come to this conclusion, the scientists wanted to know what happened to the fat in the bone marrow and the general health of the bones of mice subjected to a low-calorie diet.
Rodents were divided into four groups: a group with a normal diet, a group with a normal diet plus physical activity, a group with a normal diet having a low-calorie diet and a group with a low-calorie diet with which more is a physical activity. The mice in the latter two groups consumed 30% fewer calories than those in the first two groups. According to the United States Department of Agriculture, a moderately active woman around 30 should consume 2,000 calories per day. A 30% reduction would equate to 1,400 calories per day, an amount that can be adopted in women wishing to lose weight.
Other organs of the body may also be affected
The researchers found that while the mice in the “calorie restriction” groups lost weight well, they also had decreased bone density. And in the group of mice who also engaged in physical activity, the amount of fat in the bone marrow did decrease, but the quality and quantity of their bones were altered. So instead of making the bones more robust, physical exercise would have made them more fragile when combined with too much calorie restriction. “Even a low-calorie, highly nutritious diet can have negative effects on bone health, especially when combined with exercise,” the researchers say.
They conclude on the importance for women to take this into account because “as we get older, the health of our bones naturally begins to decline. Your calorie intake and exercise program can have a huge impact on the strength of our bones and our risk of fractures. ” To note that an ANSES scientific report published in 2012 was already showing that drastically restricting your calorie rations is not a trivial act. The study highlights harmful effects, especially for the bones but also for the heart and kidneys, and psychological disturbances, in particular severe eating disorders (anorexia, bulimia, etc.).
In another 2019 study summary dedicated to the risks associated with weight-loss dietary practices, the Agency also specified that “certain weight-loss diets may induce nutritional imbalances : too high protein and salt intake, insufficient fiber, iron, magnesium, vitamin D intake. These imbalances can lead to health problems ”. Experts have concluded that, in children and adolescents, calorie restriction, whether or not associated with protein restriction, can lead to slower growth and pubertal development. During pregnancy, this practice can slow fetal development and growth.