By Stefan Ianev, Head Of Educational Development, Clean Health Fitness Institute
So, you have been dieting hard all week and busting you’re a** in gym. The weekend is just around the corner and you know its nearly time to smash out a big nasty cheat meal. After all you are feeling tired and flat as a pancake, and you know your metabolism and associated hormones are starting to tank. This is not the time to hold back now. The almighty cheat meal is just what you need to give your metabolism a boost and kick start fat loss once again!
Or is it?
There are no doubt chronic dieting leads to a decrease in metabolic rate and associated hormones such as leptin and thyroid hormone. In fact, studies have shown that leptin levels can decrease up to 39% in 4 days and up to 54% in a week (1-3). There is also a marked decrease in anabolic hormones like testosterone and IGF-1 (4-6). What this means is that not only does fat loss stall with prolonged dieting but you also start to become increasing more catabolic in muscle tissue.
Now, while studies that have looked at re-feeding over a prolonged period have shown an upregulation in metabolic rate and associated hormones (4-7), there are no studies to date to support that acute refeeding has the same effect.
In fact, it may take up to 24 hours of re-feeding just to replenish energy substrates like muscle glycogen and intramuscular triglycerides, and 48 to 72 hours minimum to up-regulate metabolic rate and anabolic hormones. As you can see a single cheat meal will have very little if any physiological benefit. The main purpose of a cheat meal is simply for psychological purposes.
Given that adherence is the single most important factor for long-term dietary success (see The Big Picture Article), this cannot be overlooked. Knowing your favourite food is just around the corner makes it much easier to follow your nutrition plan indeed.
The question now becomes how much and how often is it acceptable to deviate from your plan?
The most common approach is to go all-out once every 5 to 7 days with no restrictions in terms of foods and portion sizes. This was the approach that I previously used to recommend. Based on experience and the latest available scientific evidence I now believe that approach is far from ideal.
Consider that a typical cheat meal for the average person is something like pizza and ice-cream, with some beer or wine. That can easily amount to 2000 to 3000 calories in a single sitting. That is sufficient to wipe out the entire weekly deficit.
Not to mention when you have been dieting your metabolism is suppressed and your lipogenic or fat storing enzymes are up-regulated. In essence your body in an energy conserving state.
What do you think will happen when you slam down 2000 to 3000 calories in that state?
Your body will simply hold onto the excess energy in anticipation of another bout of famine. And the worst part about it is that there is no impact on metabolic rate so the next day you are right back to square one.
A much smarter approach is to only create a small calorie deficit in the first place to mitigate metabolic down regulation as I discussed previously in my article ‘The Undereating Controversy” [link article]. Cheat meals should then be factored into your daily caloric intake. As a rule of thumb, I recommend that 90% of your calories come from whole, unprocessed foods. This has the benefit of improving satiety and providing your body with vital micronutrients.
The remaining 10% of your calories can come from less healthier alternatives. How you spread that out is totally up to you. I usually prefer to spread it out over the course of the week.
For example, I normally eat 6 meals a day, which equals out to 42 meals per week. That means 4 of those meals will typically be composed of foods like pizza, chocolate or ice cream that are not normally on the menu. The caloric content of each of those meals however will be close to that of my normal meals so my weekly caloric intake does not blow out.
If you prefer having your cheat meal in one bolus dose that’s fine also. Just make sure you reduce the calories in your other meals so it evens out.
In the revolutionary iNutrition Pro software that I created, clients can redistribute calories between meals so they can plan when having a big cheat meal and control the damage, which In the end that leads to much better dietary compliance and consistency!
Now go forth and cheat guilt free!
- Jenkins, A.B., et al., Carbohydrate intake and short-term regulation of leptin in humans. Diabetologia, 1997. 40(3): p. 348-51.
- Mars M, Graaf C, Groot CP, van Rossum CT, Kok FJ. Fasting leptin and appetite responses induced by a 4-day 65%-energy-restricted diet. Int J Obes (Lond). 2006 Jan;30(1):122-8.
- Keim, N.L., J.S. Stern, and P.J. Havel, Relation between circulating leptin concentrations and appetite during a prolonged, moderate energy deficit in women. Am J Clin Nutr, 1998. 68(4): p. 794-801.
- Korbonits, M., et al., Metabolic and hormonal changes during the refeeding period of prolonged fasting. Eur J Endocrinol, 2007. 157(2): p. 157-66.
- Chan, J.L., et al., The role of falling leptin levels in the neuroendocrine and metabolic adaptation to short-term starvation in healthy men. J Clin Invest, 111(9): p. 1409-21.
- Friedl, K. E, Moore, R. J, Hoyt, R. W, Marchitelli, L. J, Martinez-Lopez, L. E, & Askew, E. W. (2000). Endocrine markers of semistarvation in healthy lean men in a multistressor environment. Journal of Applied Physiology, 88(5), 1820-1830.
- Davoodi, S. H, Ajami, M, Ayatollahi, S. A, Dowlatshahi, K, Javedan, G, & Pazoki-Toroudi, H. R. (2014). Calorie Shifting Diet Versus Calorie Restriction Diet: A Comparative Clinical Trial Study. International Journal of Preventive Medicine, 5(4), 447.