A small study suggests there's no need to cut calories when dieters with obesity, diabetes or high blood pressure reduce how much protein they eat. Photo courtesy of National Cancer Institute
Sept. 21 (UPI) -- Dieting by cutting protein intake may be as effective as restricting calories for people trying to fight obesity, diabetes and high blood pressure, a small study suggests.
So, that means setting aside the steak, but passing the mashed potatoes.
The study by researchers in Brazil and Denmark, which compared the effects of protein and calorie restriction diets in patients with metabolic syndrome, was published in the journal Nutrients.
They said their findings confirmed previous studies involving experiments on mice.
According to the Mayo Clinic, as many as one in three Americans has metabolic syndrome, defined as a cluster of conditions that occur together to increase the risk of heart disease, stroke and type 2 diabetes.
These conditions include increased blood pressure, high blood sugar, excess body fat around the waist, and abnormal cholesterol or triglyceride levels.
"The study showed that cutting protein intake to 0.8 gram per kilogram of body weight was sufficient to achieve almost the same clinical results as restricting calories, but without the need to reduce calorie intake," said Rafael Ferraz-Bannitz, the study's primary author.
A postdoctoral researcher at Harvard Medical School's Joslin Diabetes Center, Ferraz-Bannitz said in a news release that dieting by restricting the amount of protein eaten may be "a more attractive nutritional strategy and easier to follow for people with metabolic syndrome."
The study was conducted by a multidisciplinary team of scientists, including those affiliated with the University of Copenhagen in Denmark and the University of São Paulo and the National Cancer Institute in Brazil.
It involved 21 volunteers with metabolic syndrome, who were analyzed for 27 days as researchers monitored their diet. Throughout the period, they were hospitalized at São Paulo's Ribeirão Preto Medical School's teaching hospital, Hospital das Clínicas in Ribeirão Preto.
Each volunteer's daily calorie intake was calculated as a function of baseline metabolism, looking at energy expenditure at rest, the release said.
One group ate what the researchers called a standard Western diet: 50% carbohydrate, 20% protein and 30% fat, but with 25% fewer calories.
The second group's protein intake was reduced to 10%, and calorie intake was tailored to each volunteer's baseline energy expenditure.
After the 27 days of monitoring, both groups had similar results in terms of lower blood sugar, weight loss, controlled blood pressure, and lower levels of triglycerides and cholesterol, the researchers said.
Both diets improved insulin sensitivity after treatment. Body fat decreased, as did waist and hip circumference, but without loss of muscle mass," Maria Cristina Foss de Freitas, a study co-author and professor at the Brazilian medical school, said in the release.
The scientists noted that decreased body fat is known to be associated with reduced blood sugar and more normal levels of lipids and blood pressure.
Despite the promising results of their research, they noted that participants' diets were personalized. And they focused on a specific population of patients with metabolic syndrome: obesity, diabetes, hypertension and abnormal levels of cholesterol.
But the researchers said it's tempting to extrapolate the results, noting research has shown vegan diets to benefit people with metabolic syndrome and that the excessive protein intake common in the standard Western diet can be a problem.