Researchers from the Salk Institute, the University of California, San Diego, and others recently found that when fruit flies stop eating at night, their heart ages slower, and in addition to this, the group also analyzed the specific molecular mechanisms involved. The findings were published in the March 13, 2015 issue of the journal Science. In 2012, Satchidananda Panda, an associate professor at the Salk Institute, found that mice fed a high-fat diet, but only for eight hours a day, were healthier and slimmer than mice fed the same amount of food throughout the day, and both groups burned the same number of calories. This led Panda et al. to point out that it’s not just what you eat that matters, but also when you eat that matters for your health, and last year the group conducted further experiments and found that the mechanism of action of time restriction is more complex than previously anticipated, which could reverse animal models of obesity and diabetes. Building on these studies, Panda’s group again found that fruit flies that fed during the day when they were more physically active and slept at night gained weight more slowly and also maintained better heart function than those that fed regardless of the time of day. Both groups of fruit flies consumed the same number of calories and performed the same intensity of exercise. But regardless of whether these fruit flies ate low-fat cereal or high-fat, the daytime-only fruit flies were simply healthier than those who ate throughout the day. To unravel the genetic mystery of this, the researchers analyzed the genetic components that encode the biological clock and found that the TCP-1 cyclic complex chaperone, as well as the mitochondrial electron transport chain complex, are the main monitoring and regulating components in this process. All of these studies show how when we eat is also important for our health. Although it is not yet possible to conduct intervention experiments in humans, this is clearly a viable approach to weight loss and, with more experimentation, may reveal what triggers obesity in the first place. Previous research has also demonstrated that for mice already suffering from obesity, restricting their diet so that they could not eat outside of nine hours also revealed that the mice lost weight. In addition to this another group of researchers discovered an important signaling system in the brain that controls appetite, energy expenditure and the body’s fat composition. One particular gene, Y6, determines body fatness. The researchers found that mice with the Y6 gene knocked out were smaller and had less non-fat tissue in their bodies than normal mice. In addition, as the mice aged, the knockout mice grew fatter than normal mice, especially when consuming high-fat foods. In this case, the mice became obese and developed diabetes-like metabolic problems. The study showed that pancreatic polypeptide (Pancreatic Polypeptide) is very closely related to Y6 in mice. This is a satiety signal that controls eating at different times. The researchers noted that consuming the same number of calories at different times of the day does not have the same effect on body weight.