Focusing on nutrition and lifestyle, we know that the causes of the rise in obesity include the overconsumption of processed foods and sugar, too few nutrient-dense foods and too-large portion sizes, as well as stress, a sedentary lifestyle, sleep disturbances, not getting enough exercise, metabolic factors, and even environmental toxins. Now, a new study by researchers from Yale University School of Medicine has taken on the challenge to answer the question from a biological standpoint: Where does all that fat come from?
The results were published online in the journal Nature Cell Biology on Feb. 24. The National Institutes of Health funded the study.
Our body stores fat in adipose cells, which collect the fat from the foods we eat, making them available when we need energy. Surrounding our internal organs and found under the skin, adipose cells help cushion the body and keep it warm. When we consume more energy than we burn, adipose cells accumulate excess fat and increase in size.
“Since lipid-laden mature adipocytes cannot divide, the increase in cell number in obesity must come from differentiation of precursor cells in the tissue,” theorized Matthew Rodeheffer, PhD, Assistant Professor of Comparative Medicine and of Molecular, Cellular, and Developmental Biology at Yale.
Using a process called differentiation, co-authors Rodeheffer and Ryan Berry isolated cells from fat and studied which ones could turn into fat cells. The researchers identified cells in mice with certain types of receptors on their surface that eventually transformed into white adipocytes, what most people recognize as fat.
The proliferation in recent decades of obesity and other related health problems, like type II diabetes, in the U.S. and other developed countries emphasizes the importance of determining how the body normally regulates fat mass is and how the process changes in obesity. Rodeheffer says scientists will now be able study how these cells act under various conditions, such as during dieting, exercise or overeating.
“Despite the high incidence of obesity and the health risks associated with it, our understanding of the basic biology of fat tissue is limited,” Rodeheffer states on his website.
According to Yale News, the researchers “hope to discover what causes the precursors to make new fat cells in obesity — and one day potentially block their creation,” which, Rodeheffer says, will keep them busy for the next 20 years.