Protein restriction may help reduce diabetes and obesity, according to a study


A study found that cutting back on protein can help control the metabolic syndrome and several of its main symptoms, including high blood pressure, diabetes, and obesity.

The journal Nutrients has published a paper summarising the study.

The term “metabolic syndrome” refers to a group of diseases, including hypertension, high blood sugar, extra body fat around the waist, and abnormal cholesterol levels, that increase the risk of diabetes, cardiovascular disease, and stroke.

“The study found that limiting protein consumption to 0.8 g per kg of body weight was sufficient to provide effects that were nearly identical to those of calorie restriction without reducing protein intake. The findings imply that one of the major contributing elements to the well-known advantages of dietary restriction may be protein restriction. Therefore, for those with metabolic syndrome, protein restriction dieting may be more appealing and simpler to stick to “said Rafael Ferraz-Bannitz, the article’s first author and a postdoctoral researcher at Harvard Medical School’s Joslin Diabetes Center in the United States.

Through a PhD grant given to Ferraz-Bannitz while he was enrolled in the University of Sao Paulo’s Ribeirao Preto Medical School (FMRP-USP) in Brazil, FAPESP provided funding for the study. The FAPESP Thematic Project on methods for simulating the effects of dietary restriction, directed by Marcelo Mori, a professor at the State University of Campinas (UNICAMP), located in Brazil, was also helpful to the study.

Researchers from the University of Copenhagen in Denmark, the University of Sao Paulo and the National Cancer Institute (INCA) in Brazil, as well as the Obesity and Comorbidities Research Center (OCRC), a Research, Innovation and Dissemination Center (RIDC) funded by FAPESP and housed by UNICAMP, made up the multidisciplinary research team that carried out the study.

regulated diet

For a total of 27 days, the diets of 21 participants with metabolic syndrome were tracked as part of the study. They were patients at the teaching hospital of FMRP-USP during that time (Hospital das Clinicas in Ribeirao Preto).

Based on each volunteer’s initial metabolism, daily caloric intake was determined (energy expenditure at rest). A conventional Western diet of 50% carbohydrates, 20% protein, and 30% fat was served to one group, although it had 25% fewer calories.

The protein intake for the second group was lowered to 10%. Each volunteer’s calorie intake was adjusted based on their initial energy usage. 4 grammes of salt were ingested daily by both groups.

The outcomes demonstrated improved metabolic syndrome symptoms and weight loss in both the protein restriction and calorie restriction groups due to a reduction in body fat. It is well known that less body fat is linked to lower blood sugar, more normal levels of lipids, and normal blood pressure.

“Both groups saw similar outcomes in terms of decreased blood sugar, weight loss, controlled blood pressure, and lower levels of triglycerides and cholesterol after 27 days of observation. Following therapy, both diets enhanced insulin sensitivity. Without losing muscle mass, body fat dropped, as did the waist and hip circumferences “Maria Cristina Foss de Freitas, the article’s final author and a professor at FMRP-USP, stated.

The results corroborated earlier research that used mouse experiments. But in this case, Foss de Freitas added, “we managed to execute a thoroughly controlled randomised clinical study spanning 27 days, with a customised menu planned to fit each patient’s needs.”

To achieve the positive effects of dietary restriction, manipulation of the macronutrients protein, carbohydrate, and fat in the diet is sufficient. “We showed that limiting protein results in a decrease in body fat while preserving muscle mass. That’s crucial since the weight reduction brought on by restricted diets is frequently accompanied by a decrease of muscle mass “said Ferraz-Bannitz.

Although the study did not look into the molecular mechanisms that might underlie the advantageous effects of protein restriction diets, the researchers do believe that low protein intake changed the metabolism or improved the body’s ability to manage its energy by encouraging it to burn fat instead of carbohydrates to fuel cells. “So far, all we have are hypotheses. One is that when necessary amino acids are depleted, cellular pathways are engaged to read this as a signal to eat less while also producing hormones that generally rise during fasting “explained Mori. Studies using animal models have demonstrated how these pathways are affected by protein restriction and calorie restriction, both of which promote fat reduction.

The researchers remind out that the diets used were customised despite the positive findings of their experiments. Mori emphasised that they concentrated on a particular group of patients with metabolic syndrome (obesity, diabetes, hypertension and abnormal levels of cholesterol).

“However, it’s alluring to extend the findings. We are aware that research has linked vegan diets to lower rates of metabolic syndrome. Additionally, it has been discovered that the high protein intake that is typical of the Western diet can be problematic. Every situation needs to be examined on its own merits. Protein deficit can cause serious health issues, as has been well-documented in pregnant women, for instance “Added he.