Little appetite for obesity: meta-analysis of the effects of maternal obesogenic diets on offspring food intake and body mass in rodents

BACKGROUND: There is increasing recognition that maternal effects contribute to variation in individual food intake and metabolism. For example, many experimental studies on model animals have reported the effect of a maternal obesogenic diet during pregnancy on the appetite of offspring. However, the consistency of effects and the causes of variation among studies remain poorly understood. METHODS: After a systematic search for relevant publications, we selected 53 studies on rats and mice for a meta-analysis. We extracted and analysed data on the differences in food intake and body weight between offspring of dams fed obesogenic diets and dams fed standard diets during gestation. We used meta-regression to study predictors of the strength and direction of the effect sizes. RESULTS: We found that experimental offspring tended to eat more than control offspring but this difference was small and not statistically significant (0.198, 95% highest posterior density (HPD) = -0.118-0.627). However, offspring from dams on obesogenic diets were significantly heavier than offspring of control dams (0.591, 95% HPD = 0.052-1.056). Meta-regression analysis revealed no significant influences of tested predictor variables (for example, use of choice vs no-choice maternal diet, offspring sex) on differences in offspring appetite. Dietary manipulations that extended into lactation had the largest effect on body weight. Subgroup analysis revealed that high protein to non-protein ratio of the maternal diet may promote increased body weight in experimental offspring in comparison with control offspring; low protein content in the maternal chow can have opposite effect. CONCLUSIONS: Exposure to maternal obesogenic diets in early life is not likely to result in a substantial change in offspring appetite. Nevertheless, we found an effect on offspring body weight, consistent with permanent alterations of offspring metabolism in response to maternal diet. Additionally, it appears that protein content of the obesogenic diet and timing of manipulation modulate the effects on offspring body weight in later life.