Intake of total, animal and plant protein and subsequent changes in weight or waist circumference in European men and women: the Diogenes project

Abstract

Background: As protein is considered to increase thermogenesis and satiety more than other macronutrients, it may have beneficial effects on prevention of weight gain and weight maintenance. Objective: The objective of this study is to assess the association between the amount and type of dietary protein, and subsequent changes in weight and waist circumference (WC). Methods: 89 432 men and women from five countries participating in European Prospective Investigation into Cancer and Nutrition (EPIC) were followed for a mean of 6.5 years. Associations between the intake of protein or subgroups of protein (from animal and plant sources) and changes in weight (g per year) or WC (cm per year) were investigated using gender and centre-specific multiple regression analyses. Adjustments were made for other baseline dietary factors, baseline anthropometrics, demographic and lifestyle factors and follow-up time. We used random effect meta-analyses to obtain pooled estimates across centres. Results: Higher intake of total protein, and protein from animal sources was associated with subsequent weight gain for both genders, strongest among women, and the association was mainly attributable to protein from red and processed meat and poultry rather than from fish and dairy sources. There was no overall association between intake of plant protein and subsequent changes in weight. No clear overall associations between intakes of total protein or any of the subgroups and changes in WC were present. The associations showed some heterogeneity between centres, but pooling of estimates was still considered justified. Conclusion: A high intake of protein was not found associated with lower weight or waist gain in this observational study. In contrast, protein from food items of animal origin, especially meat and poultry, seemed to be positively associated with long-term weight gain. There were no clear associations for waist changes.

Dietary Protein Intake and Incidence of Type 2 Diabetes in Europe: The EPIC-InterAct Case-Cohort Study

“…We found that the association between protein intake and type 2 diabetes was strongest in obese women in contrast to prior research declaring weaker associations with increasing BMI (3). Our findings may be explained by the fact that higher total protein intake, and/or higher protein intake from animal sources, is associated with weight and weight gain (31,32). In our data, this effect would be stronger in women than in men.…”

Main nutrient patterns are associated with prospective weight change in adults from 10 European countries

“…At the nutrient level, we are suspecting the high protein intake (~19 E % in the highest quintile of PC4- Table 2) combined with a low intake of dietary fiber (~11 g/day) being responsible for the positive associations with weight gain. Despite the convincing evidence from RCT and physiological studies that a high protein intake is beneficial for weight loss and control in the short-term, longer-term and/or large-scale observational studies have reported the opposite [29][30][31]. The effects of dietary nutrient mixtures on appetite and weight control are poorly understood.…”

Body Characteristics, Dietary Protein and Body Weight Regulation. Reconciling Conflicting Results from Intervention and Observational Studies?

“…The participants in the DiOGenes trial [5], showing better weight loss maintenance with a high protein intake, were matched on gender, diet and body characteristics in the observational Danish Diet, Cancer and Health (DCH) cohort study, showing a tendency to weight gain with greater protein intake [6].…”

“…Randomized, controlled trials (RCTs) have suggested an overall beneficial effect of high-protein diets on weight loss and weight maintenance after weight loss [4], [5]. In contrast, large-scale, long-term observational cohort studies have shown that greater protein intake is associated with weight gain [6], [7]. Although results from RCTs and observational studies often reach similar results [8]–[12], the sometimes conflicting findings make the formation of health recommendations difficult.…”