When it comes to maintaining a productive weight loss routine, dietary cheaters can actually win. That’s because allowing yourself a weekly cheat meal can not only ward off cravings, but it can also alleviate the stress produced by dieting as well as boost your metabolism by increasing levels of leptin, the satiety hormone responsible for sending appetite-suppressing messages to the body. But if your indulgent habit turns into a cheat weekend, a new study suggests you may be damaging your health just as much as having a regular diet of junk food.
Led by Dr. Margaret Morris from Australia’s University of New South Wales, this study examined the impact of “yo-yo” dieting on the gut microbiota of rats. Disrupting the composition of the human gut—which consists of up to 100 trillion microbial cells that influence nutrition, metabolism, and immune function—through repetitive changes in diet has been associated with obesity. The study compared the microbiota between groups of rats given either continuous access to a healthy diet, continuous access to high-fat, energy-rich junk food, or cycled access between the two diets (healthy for four days and junk for three), to uncover how diet can influence gut health and obesity.
After 16 weeks, rats on the cycled diet were 18 percent heavier than those on the healthy diet. Researchers also found the microbiota of cycled rats was nearly indistinguishable from rats fed the junk food diet. Specifically, consuming junk food reduced the beneficial microbial species that can metabolize omega-3s and flavonoids (antioxidants which assist in weight loss, as well as provide protection from neurodegenerative diseases). Also of note, cycled rats showed large swings in food intake when they switched between each diet. Relative to the rats with continuous healthy diets, cycled rates over-consumed up to 30 percent more energy during splurges and under-consumed almost 50 percent less energy when eating healthily.
What does this all mean? Binging on junk food—even if it’s just three days a week—will not only cause you to gain weight and eat more unhealthy calories, but it can also shift your gut microbiota towards the same pattern that has been associated with obesity. Dr. Morris explained, "While these findings are yet to be replicated in humans, those who are strict with their diet during the week may be undoing all their good work by hitting the junk food over the weekend." So be sure to keep cheat meals as cheat meals, and to help you do so, check out our 20 Cheat Meal Tips for Weight Loss Success!