Metabolism can also be altered with clinical consequences similar to caloric restriction
Studies have shown that diets that limit protein intake are effective in fighting obesity and diabetes. This is the content of a study by a research team at the University of Sao Paulo, Brazil, comparing the effects of a protein and calorie restricted diet on patients with metabolic syndrome.
According to a new study, reducing protein intake could help manage key symptoms of metabolic syndrome, including obesity, diabetes and high blood pressure. Metabolic syndrome refers to a disease that increases the risk of diabetes, cardiovascular disease, stroke, such as high blood pressure, high blood sugar, excess body fat around the waist, and abnormal cholesterol levels.
“This study shows that reducing protein intake to 0.8 g/kg of body weight is sufficient to achieve clinical results almost equivalent to caloric restriction,” said Rafael Ferraz-Banitz, first author and postdoctoral researcher present at the Diabetes Center, Harvard Medical School, USA “It shows that there is no need to reduce caloric intake,” he said. “A protein-restricted diet may be a more attractive nutritional strategy for people with metabolic syndrome.”
This study targeted 21 patients with metabolic syndrome over 27 days. During the study period, the participants were hospitalized at the Hospital of the University of São Paulo.
Daily caloric intake was determined for each participant as a function of basal metabolism. The first group was given a traditional Western diet of 50% carbohydrates, 20% protein, and 30% fat, but with 25% less total calories. The second group reduced their protein intake to 10%. Each participant’s caloric intake was matched to their baseline energy expenditure. Both groups ate 4 grams of salt each day.
As a result, due to the reduction in body fat, the calorie restriction and protein restriction groups lost weight, and the symptoms of metabolic syndrome improved. A reduction in body fat is known to be associated with a reduction in blood sugar and more normal levels of lipids and blood pressure.
Professor Maria Cristina Fos de Freitas from the University of Sao Paulo said, “As a result of observation over 27 days, both groups showed similar results in terms of lowering blood sugar, losing weight, controlling blood pressure, and lowering triglyceride and cholesterol levels. “Insulin sensitivity improved after treatment.” He added, “Body fat decreased as did waist and hip circumference, but muscle mass did not.”
This study confirmed the results of previous studies, including rat experiments. “We have managed to conduct a fully controlled randomized clinical trial of 27 days with a personalized menu designed to meet the needs of each patient,” explains Professor Fos de Freitas.
Manipulation of dietary macronutrients such as proteins, carbohydrates and fats is sufficient to obtain the beneficial effects of dietary restriction. “We have shown that restricting protein reduces body fat while preserving muscle mass,” says researcher Ferraz-Banitz. “This is important because weight loss from calorie-restricted diets is often associated with loss of lean muscle mass.”
This study did not investigate molecular mechanisms that might explain the beneficial effects of a protein-restricted diet. However, the research team believes that a low intake of protein improves the organism’s energy management by triggering changes in metabolism or inducing it to burn fat to produce energy for cells.
Despite the promising findings, each case should be analyzed on its own merits. As the study targeted patients with a target syndrome and provided the participants with a personalized diet, it is difficult to generalize. For example, pregnant women should remember that a lack of protein can lead to serious health problems.
The study was published in ‘Nutrition’. The original title is ‘Dietary Protein Restriction Improves Metabolic Dysfunction in Patients with Metabolic Syndrome in a Randomized Controlled Trial’.
