When it comes to fighting obesity, new research indicates it’s not only how much you eat, but also when you eat that’s important.
Scientists at SickKids Hospital in Toronto investigated a process known as intermittent fasting, a strategy where you insert brief fasting periods into your diet. Specifically, they looked at a repeating pattern of two days of normal eating, followed by one day of fasting and found substantial associated health benefits.
Mice that intermittently fasted gained less weight than their non-fasting counterparts and had more stable glucose levels, an important factor in diabetes prevention. Furthermore, the researchers tested intermittent fasting as a therapy for obesity. In the study, obese mice on an intermittent fasting regime lost more weight, particularly in adipose tissue or fat, than obese mice who ate regularly. The research was published last month in Cell.
Intermittent fasting isn’t a new idea in the scientific community – the benefits extend beyond metabolic changes and range from slowing aging to preventing cardiovascular and neurodegenerative disease. Intermittent fasting, however, typically results in a net calorie deficit, which makes it difficult to tell if the positive effects are due to the change in eating pattern or just a result of eating less. In this new article, the team disentangled the two factors, showing that intermittent fasting, independent of caloric restriction, is directly causing the observed metabolic benefits.
But how exactly is changing your eating patterns altering the effects of food on your body?
It turns out that intermittent fasting favourably alters fat tissue, converting inactive white fat into energy-burning brown fat. White fat has been linked to obesity and type-2 diabetes whereas brown fat is more sensitive to insulin and increases energy expenditure. Interestingly, the metabolic benefits of white adipose tissue browning have been previously established in a different process – physical exercise. It seems that the intermittent fasting has similar effects on fat tissue as going for a run.
The team of researchers went further, and identified vascular endothelial growth factor, or VEGF, as the critical gene in orchestrating the fasting-induced fat changes. When VEGF was eliminated, the benefits of fasting disappeared. Conversely, periodically upregulating the VEGF expression mimicked the effects of fasting.
Next, the team plans to test whether intermittent fasting causes similar metabolic benefits in humans, and determine a fasting period that is effective but also feasible for everyday life. In addition, they suggest that selectively activating VEGF expression in adipose tissue represents a potential therapeutic avenue for obesity and other metabolic diseases.
So, next time you’re worrying about what to make for dinner, the best thing for your health might be to put it off until the next day.