The study involved overweight adult patients from eight European countries who followed a low-calorie diet (800 kcal) and achieved weight loss of at least 8% of the original body weight. The participants in the study were divided according to their own desire into 5 groups formed by the factorial method paired according to the diet followed: (1) low in protein and low glycemic index, (2) low in protein and high glycemic index, (3) with high proteins and high glycemic index, (4) high proteins and low glycemic index or (5) control diet. The patients were followed for 26 weeks to monitor the effectiveness of each of the regimens in maintaining the body weight achieved.

A total of 1,209 adult patients (average age 41 years, BMI 34 kg / m²;) were included in the screening, of which 938 patients received a low-calorie diet. 773 patients who succeeded in fully adhering to a low-calorie diet were randomly divided into five groups according to the maintenance diet, 548 people (71%) completed the study. The largest number of patients excluded from the study was recorded in the diet group with a high glycemic index and a low protein content compared to the participants in the protein rich or low glycemic index groups (37.4% versus 26.4% and 25.6%, P = 0.02 and P = 0.01, respectively). On average, the weight loss at the end of a low-calorie diet was 11 kg. When analyzing weight gain among study participants who completed it, only a low protein, high glycemic index diet was associated with significant weight gain (1.67 kg, 95% confidence interval 0.48-2.87). When performing the analysis according to the prescribed intervention (ITT analysis), the weight gain was 0.93 kg less (95% confidence interval 0.31-1.55) in the following participants a diet rich in protein compared to low p = 0.003) and 0.95 kg lighter (95% confidence interval 0.33-1.57) in groups of patients following a diet with a low glycemic index compared to a high index (p = 0.003). In the groups, there was no significant difference in the development of adverse events.

Thus, as the results of this large-scale study show, a moderate increase in the protein content and a decrease in the glycemic index of the products consumed led to an improvement in patient compliance and the maintenance of the desired weight achieved.

Unfortunately, for the moment, it is impossible to say with 100% certainty that maintaining a normal body weight will lead to a reduction in cardiovascular risk. According to scientists, the subject of further research is an important aspect of the influence of the maintenance of normal body mass on the state of the cardiovascular system.

During the study, interesting details were discovered. In addition to the participants themselves, the study included all of their family members. The researchers noticed that the number of obese or overweight children decreased significantly precisely in families in which low-glycemic and high-protein foods were consumed, and there were no quantitative restrictions.

During the study, as the scientists themselves admit, there was no qualitative accounting of the proteins consumed, which would probably be of particular interest for cardiologists. Although, according to the researchers, the proteins of animal origin ingested in each of the eight participating countries were likely to differ. In addition, according to the researchers, the effectiveness of products with high protein content, whatever their plant or animal origin, in terms of keeping the weight at the right level should be comparable.

Active discussions are underway regarding the effect of saturated fat compared to other types of lipids and carbohydrates on health status, and not only cardiovascular disease, but also oncology deserve special attention.

According to the researchers, they will need to rely on their own data to make a more reliable assessment of the potential effects of cholesterol - positive and negative. At the same time, there are reports in the literature regarding the lack of differences in the amount of weight lost when observing various popular diets today. According to some researchers, a person's ability to stay on a diet for a long time depends to some extent on how the diet affects hunger and metabolism. More research is needed to clarify the mechanisms by which the building blocks of food regulate body weight and to develop new qualitative strategies that can change eating behavior.