Diet six days a week, and on the seventh eat absolutely anything. What's not to love about that? Apparently, a lot. The idea of a "cheat day," or choosing to take a day off from strict dieting, stirs up some serious debate in the health world. So we went to the root of the issue: Can choosing to cheat actually be healthy?

What Is Cheating?


There are generally three beliefs about what constitutes "cheating":

  1. The idea that a during a set period of time (usually either one day or one meal).
  2. Cheating as making a to eat specific things normally avoided for health reasons (like fructose to prevent a glucose spike, caffeine to boost energy, and so on).
  3. Accepting that cheating is a natural part of dieting, and therefore isn't really "cheating" at all, says Glamourgirlz expert Lindsey Joe.

Physical Effects of Cheating

One of the pro-cheating claims is that cheat days boost metabolism by upping leptin production (we'll explain that in a second), helping the body burn more calories after overeating. Some studies do support this claim, but others suggest overfeeding (the scientific phrase for eating too much, or "cheating") only ups metabolism between three and 10 percent for no more than 24 hours, making the little boost not worth the hundreds or thousands of extra calories Katzeff, H.L., O'Connell, M., Horton, E.S., et al. Metabolism: Clinical and Experimental, 1986 Feb;35(2):166-75. Dirlewanger, M., di Vetta, V., Guenat, E., et al. Institute of Physiology, University of Lausanne, Switzerland. International Journal of Obesity and Related Metabolic Disorders, 2000 Nov;24(11):1413-8..

But the diet-rejuvenating effect of a cheat day may amount to more than just burning a few extra calories. (as most people do when dieting) can cause , a hormone responsible for maintaining our energy balance and causing weight loss, to dwindle. But temporarily upping calorie intake can re-up leptin production by nearly 30 percent (for up to 24 hours) Pratley, R.E., Nicolson, M., Bogardus, C., et al. Clinical Diabetes and Nutrition Section, Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Arizona 85016, USA. The American Journal of Pysiology, 1997 Sep;273(3 Pt 1):E644-9. Dirlewanger, M., di Vetta, V., Guenat, E., et al. Institute of Physiology, University of Lausanne, Switzerland. International Journal of Obesity and Related Metabolic Disorders, 2000 Nov;24(11):1413-8.. It's that quick leptin buzz that's responsible for boosting metabolism after overeating. And in addition to regulating hunger and metabolism, this hormone may contribute to increased motivation, libido, and — so after a cheat day, dieters might actually be happier and more motivated Jéquier, E. Institute of Physiology, University of Lausanne, Switzerland. Annals of the New York Academy of Sciences, 2002 Jun;967:379-88. Davis, J.F. Department of Psychiatry, University of Cincinnati, Cincinnati, OH 45237, USA. Discovery Medicine, 2010 May;9(48):462-7. Hausman, G.J., Barb, C.R. USDA/ARS, Richard B. Russell Agriculture Research Center, Athens, GA, USA. Endocrine Development, 2010;19:31-44. Opland, D.M., Leinninger, G.M., Myers, M.G., Jr. Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA. Brain Research, 2010 Sep 2;1350:65-70..

It's the combined benefits of leptin that lead "cheat days" filled with foods (as opposed to anything and everything they want). For example, one study found overeating on a high protein diet increased resting metabolism, while overeating on a low protein diet did not Bray, G.A., Smith, S.R., de Jonge, L., et al. Pennington Biomedical Research Center, 6400 Perkins Rd, Baton Rouge, LA 70808, USA. The Journal of the American Medical Association, 2012 Jan 4;307(1):47-55.. In another study, resting metabolism was only increased by carb bingeing— not from eating lots of fatty foods (think pizza and ice cream) Dirlewanger, M., di Vetta, V., Guenat, E., et al. Institute of Physiology, University of Lausanne, Switzerland. International Journal of Obesity and Related Metabolic Disorders, 2000 Nov;24(11):1413-8.. And while cheat days often involve binge drinking in addition to binge eating, alcohol actually has . Fortunately, one study did find red wine was an exception to the rule (phew!)— but only in women Djurovic, S., Berge, K.E., Birkenes, B., et al. Department of Medical Genetics, Ullevaal University Hospital, N-0407 Oslo, Norway. Alcohol and Alcoholism, 2007 Nov-Dec;42(6):525-8.. So for anyone keeping score at home, that's a high-protein, high-carb, low-fat, and alcohol-free (unless you're a woman— then you can have red wine only) cheat day. Sounding less and less like a carefree free-for-all, huh?

It's also especially important for anyone with a health condition (like diabetes, high cholesterol, blood pressure, etc.) to plan carefully, as even small indulgences can have more larger effects on health. Consider the overall balance of macronutrients in a dietary splurge— sweets may be fine, but look for those also high in essential nutrients like protein and fiber, explains Glamourgirlz expert Dr. Douglas Kalman.

Psychological Effects of Cheating

But then there's the whole other side of the cheating equation: psychology. Psychologists and nutritionists often believe allowing a cheat meal or cheat day to satisfy a craving allows people to stick to otherwise restrictive diets, Kalman explains. Other accept that people will only really adhere to a strict diet about 80 percent of the time. The other 20 percent is like built-in cheating. Diet gurus like Mark Sisson, the creator of the Primal Blueprint, and a similar ideology.

The key, according to Joe, is getting past the guilt of assigning "good" and "bad" tags to various foods. Rather than turning a minor slip-up into a major back-slide, she says cheaters should simply accept what they ate, and continue with their diet as planned.

All in all, it appears calculated cheating can boost the benefits of an otherwise restrictive (read: low-cal) diet. No holds barred bingeing, however, can be dangerous and may even set off a problematic psychological chain reaction. For those who wish to indulge without all the scientific calculations, focus on rather than substituting an entire meal of unhealthy foods for a healthy one.

The Takeaway

  • There are a lot of different ways to think of cheat days— from all-out free-for-alls, to scientific calculations, or simply a psychological paradigm shift.
  • Overeating can increase leptin production, which in turn boosts metabolism. Leptin also contributes to motivation, libido, and dopamine production.
  • To increase leptin production without completely unhinging a diet, a high-protein, high-carb, low-fat, and alcohol-free cheat day may be the key.
  • Psychologically, it may be effective to accept that it's only possible to stick to a diet about 80 percent of the time. The other splurges are totally natural and a-okay.
Photo by Caitlin Covington