If your life-change goals include losing weight, nodoubt you’ve tried the wild weekend strategy—eating healthy food Monday through Friday, and hoping weekend overeating doesn’t catch up with you.. But new Australian research finds that even if you don’t gain weight, those end-of-week excesses play havoc with the microbes that make your gut function effectively, undermining metabolism, nutrition, the immune system and even your mental health. In fact, as far as the 100 trillion or so microbes lining your gut are concerned, a few days a week of eating junk food is as harmful as eating that way all the time.
How Not To Lose Weight
Even if you don’t gain weight, those end-of-week excesses play havoc with the microbes that make your gut function effectively, undermining metabolism, nutrition, the immune system and even your mental health
“The diversity of the biota seems to be important for gut health,” explains Margaret Morris, Ph.D., professor of pharmacology, University of New South Wales, Australia, and the lead author. With such factors as genetics, diet, antibiotic use, exercise and hygiene all playing a role, “a recent study in humans showed that those who had the greatest diversity had lower levels of inflammatory markers.” And disrupted biomes are linked to inflammatory bowel disease and obesity.
This study, the first to compare occasional unhealthy eating with consistently healthy diets, looked at the impact of yo-yo dieting on rats. Some rats followed a low-fat diet four days a week then binged on tasty, high-fat foods for three days, simulating a long weekend. Others followed a consistently healthy diet, while a third group got as much junk food (including cake, biscuits, meat pies and chips) as they wanted. After 16 weeks, the weekend-binging rats had gained less weight than the rodents that ate junk food constantly, but were 18% heavier than the healthy-eating rats. Their gut biota, however, was virtually the same as those that ate nothing but junk. The weekend-bingers also had fewer of the microbial species that are capable of metabolizing flavonoids, important both for weight loss and protecting brain function.
Morris,who was surprised at the extent of the shift,says the study is just one more reason to eat healthy food on weekends,, as well as eat consistently for a healthier gut: “That means a diverse diet of fresh foods, including those that are high in fiber and low in saturated fat.”