Reducing protein intake can help control obesity, diabetes and high blood pressure

Reducing protein intake can help control metabolic syndrome and some of its main symptoms, such as obesity, diabetes and hypertension (high blood pressure), according to a study by researchers in Brazil and Denmark comparing the effects of protein and calorie-restricted diets in humans. An article about the study was published in the journal Nutrients.

Metabolic syndrome is a group of conditions that increase the risk of cardiovascular disease, stroke, and diabetes, including high blood pressure, high blood sugar, excess fat around the waist, and abnormal cholesterol levels.

The study showed that reducing protein intake to 0.8 grams per kilogram of body weight was sufficient to achieve approximately the same clinical results as calorie restriction, but without the need to reduce caloric intake. The results suggest that protein restriction may be one of the main factors leading to the known benefits of dietary restriction. Therefore, a protein-restricted diet may be a more attractive and easy-to-follow nutritional strategy for people with metabolic syndrome.”

Rafael Ferraz-Banitz, first author of the article and currently a postdoctoral researcher at Joslin Diabetes Center, Harvard Medical School, US

The study was funded by FAPESP through a doctoral scholarship awarded to Ferraz-Bannitz while attending the University of São Paulo Ribeirão Preto Medical School (FMRP-USP) in Brazil. The study also benefited from the FAPESP thematic project on strategies to mimic the effects of dietary restriction, led by Marcelo Mori, a professor at the State University of Campinas (UNICAMP), also in Brazil.

The study was conducted by an interdisciplinary team of scientists, including researchers affiliated with the University of Copenhagen in Denmark, the University of São Paulo and the National Cancer Institute (INCA) in Brazil, as well as the Obesity and Comorbidities Research Center (OCRC), the Research, Innovation and Publishing Center (RIDC) funded by Accepted by FAPESP and hosted by UNICAMP.

controlled diet

In the study, 21 volunteers with metabolic syndrome were analyzed for 27 days during which their diet was monitored. Throughout this period, they were inpatients at the FMRP-USP Teaching Hospital (Hospital das Clinicas in Ribeirão Preto).

The daily calorie intake for each volunteer was calculated as a function of basic metabolism (resting state energy expenditure). One group was fed what the authors call a standard Western diet (50% carbohydrate, 20% protein, 30% fat) but with 25% fewer calories.

For the placebo group, protein intake was reduced to 10%. Calorie intake is tailored to each volunteer’s baseline energy expenditure. Both groups consumed 4 g of salt per day.

The results showed that both the calorie and protein groups lost weight due to the decrease in body fat and that symptoms of metabolic syndrome improved. It is well known that lower body fat is associated with lower blood sugar and higher levels of normal lipids and blood pressure.

“After 27 days of observation, both groups had similar results in terms of lower blood sugar, weight loss, blood pressure control, and lower triglyceride and cholesterol levels. Both regimens improved insulin sensitivity after treatment. Body fat was reduced, as was waistline. “Hip circumference, but without the loss of muscle mass,” said Maria Cristina Vos de Freitas, the final author of the article and a professor at FMRP-USP.

The results confirmed the results of previous studies that included experiments on mice. “Here, however, we have successfully conducted a fully randomized, controlled, 27-day clinical trial, with a customized menu tailored to each patient’s needs,” Vos de Freitas said.

Manipulating the estimated macronutrients in the diet – protein, carbohydrates, and fats – is sufficient to obtain the beneficial effects of dietary restriction. “We’ve demonstrated that protein restriction reduces body fat while preserving muscle mass. This is important because weight loss from restrictive diets is often associated with loss of muscle mass,” said Ferraz-Panitz.

The study did not investigate the molecular mechanisms that could explain the beneficial effects of protein-restricted diets, but the researchers believe that low protein intake caused a change in metabolism or improved energy management of the organism by prompting it to burn fat in order to produce energy for cells. . “We only have hypotheses so far. One is that molecular pathways are activated to explain the decrease in essential amino acids as a signal to reduce food intake while leading to the production of hormones that normally increase when we are fasting,” Morey said. . “Studies in animal models have implicated such pathways in the effects of both protein and calorie restriction, both of which lead to fat loss.”

Despite the promising results of their studies, the researchers suggest that the diets in question were customized. Morey also emphasized that they focus on a specific category of patients with metabolic syndrome (obesity, diabetes, high blood pressure, and abnormal cholesterol levels).

“However, it is tempting to extrapolate the results. We know that research has shown that vegetarian diets are positive in cases of metabolic syndrome. It has also been found that excessive protein intake common in the standard Western diet can be problematic. Every case should be.” It was analyzed on the basis of its own merits. We should not forget that a lack of protein can lead to serious health problems, as it has been well prescribed in pregnant women, for example. “


Journal reference:

Ferraz Banitz, R.; et al. (2022) Dietary protein restriction improves metabolic dysfunction in patients with metabolic syndrome in a randomized controlled trial. Nutrients.