Does eating healthy make you store fat at the right place?

It is generally well accepted that people with healthy eating habits are more likely to have an ideal body weight compared to those with poor eating habits. However, individuals who have an ideal body weight could nevertheless be at risk of type 2 diabetes and cardiovascular diseases if they have an elevated amount of abdominal or liver fat. Several factors influence body fat distribution and include, among others, sex, ethnicity and physical activity habits. So far, few well-powered studies have sought to determine whether there was an association between nutritional quality and body fat distribution.

The association between dietary quality and adipose tissue distribution was the topic of a recent study conducted by the investigators of the Multi-Ethnic Study of Atherosclerosis and published in Nutrition, Metabolism and Cardiovascular Disorders. In this study, 5079 men and women from four ethnic groups (Caucasians, Chinese-Americans, African-Americans and Hispanics) completed a food-frequency questionnaire and underwent a computed tomography scan to measure intra-abdominal (visceral), abdominal subcutaneous, liver and pericardial (around the heart) fat. A dietary quality score was assessed and those with the highest score were those who consumed more fruits, vegetables, whole grains, fish, legumes, seeds and nuts, yogurt, alcohol in moderation and less red and processed meats and sugar-sweetened beverages.

Results of this study showed that participants with a high dietary quality score weighed on average 5 kg less than participants with a lower dietary quality score (based on the comparison of top vs. bottom quartiles). Interestingly, the authors also found that these participants had lower intra-abdominal, liver and pericardial fat, but had a comparable amount of abdominal subcutaneous fat (a depot that efficiently store fat and that is not associated with poor cardiometabolic health, unlike the other studied adipose tissue depots). In investigating the association between specific components of the diet, the authors found that a high consumption of fruits, vegetables, legumes, and fish were associated with a more positive body fat distribution patterns while red and processed meats and sugar-sweetened beverages were associated with higher intra-abdominal, liver and pericardial fat.

In light of these results, the authors suggested that the association between healthy eating and an overall positive body fat distribution pattern could be due to the impact of healthy eating on epigenetic alterations and gut microbial diversity or the impact of poor eating habits on adipose tissue inflammation and oxidative stress. Interestingly, although this was not the objective of the study, two important differences between those with ideal vs. poor dietary habits were found. Indeed, the number of participants with an income higher than $100,000 per year and the number of participants who completed at least four years of college were twice as prevalent in the best eating quality category compared to the worst eating quality category which suggests that the socio-economic status is likely to influence the relationship between eating habits and body fat distribution. In conclusion, results of this study suggest that the benefits of healthy eating go far beyond its impact on total body weight and that improving nutritional quality may not ultimately result in spectacular changes in body weight but could significantly improve cardiometabolic health by decreasing the dangerous inner body fat in the abdomen, the liver and around the heart.