It's not entirely your fault if you're not losing weight.
New research published in Nature Communication suggested that the fatter we are, the more it is difficult to lose weight due to stored fat. According to an international team of researchers from the Wellcome Trust-Medical Research Council Institute of Metabolic Sciences at the University of Cambridge, UK and Toho University, Japan, our body naturally produces proteins which act as barriers that prevent us from burning fat. The University Herald informed that the protein, identified as sLR11, suppresses the calorie burning process.
According to the authors, the sLR11 protein aids fat cells to resist burning fats in "spikes" during the metabolic process -- after large meals or short term drops in temperature. Science Daily reported that the phenomenon helps adipose tissue in storing storing energy for long time periods.
To prove their hypothesis, the authors examined mice and investigated why those that do not possess the gene for the production of the sLR11 protein were more resistant to weight gain. It is worth noting that humans share mice's tendency to increase their metabolic rate slightly upon upgrading from a lower calorie to a higher calorie diet. Based on the lab investigation, mice that lack the gene were able to burn calories much quicker than normal.
The researchers then proceeded to examining if their findings applied to human beings. When they saw sLR11 in humans, they discovered that protein found in human blood correlated with one's total fat mass. This means that the greater the levels of the protein, the higher the total fat mass. Further affirming that sLR11 is produced by fat cells, the authors found that obese patients who underwent bariatric surgery had a postoperative weight loss directly proportional to the decrease in their sLR11 levels. As a remarkable conclusion, the researchers noted that sLR11 "binds to specific receptors on fat cells" to prevent them from undergoing thermogenesis.
"Our discovery may help explain why overweight individuals find it incredibly hard to lose weight. Their stored fat is actively fighting against their efforts to burn it off at the molecular level," Dr. Andrew Whittle, joint first author of the study, said.
Lead author Professor Toni Vidal-Puig, added: "We have found an important mechanism that could be targeted not just to help increase people's ability to burn fat, but also help people with conditions where saving energy is important such as anorexia nervosa."
The findings open opportunities for the better treatment of obesity and other metabolic diseases.