I routinely review 80 plus studies a month related to nutrition and health and this one grabbed my attention like no other. In this meticulously controlled investigation, researchers had 39 healthy normal weight adult men and women purposely eat 750 extra fat calories a day for seven weeks with the goal of gaining 3% of their starting weight. One half of the study subjects consumed their extra fat calories from saturated fat while the other half consumed their extra fat calories from polyunsaturated fat. The diets were otherwise identical.
As expected, both groups gained comparable amounts of weight, but there were striking differences in both the location of the weight gained and the composition of the weight gained (really fascinating!). Specifically – those consuming the extra saturated fat experienced a markedly greater increase in visceral (belly) fat relative to those consuming the polyunsaturated fat. Additionally, the saturated fat eaters gained more total body fat and less muscle mass. Those eating the polyunsaturated fat gained three times more muscle mass and much less total and belly fat. (Diabetes, February 2014 DOI: 102337/db13-1622 1939-327X)
The implications of this study for overall health are ENORMOUS as belly fat is the type of fat that leads to heart attacks, diabetes, metabolic syndrome, dementia, and some cancers while gaining or even maintaining muscle mass is profoundly beneficial for overall metabolic health, weight control, functionality and quality of life.
Bottom line – It is the type of fat that you eat that really matters.