Leptin is a “master” hormone that has influence over many other downstream hormones like growth hormone and testosterone, which are important for preserving lean mass (which keeps your metabolism from slowing more than it would otherwise), as well as your appetite.
Yesterday, I referenced a study (Weigle, 1997) that found that if you cut calories too low, for too long, your leptin levels plummet. We also learned that this sends your body into starvation mode and you start eating (Jequier, 2002). You can fight this for a little bit, but eventually, your hormones win.
But what if you could “trick” your body and keep your leptin elevated even when you are restricting calories?
In the 1997 Weigle study, they also looked at how leptin levels reacted to refeeding after a short term fast (3 days). The found that the leptin level returned to their baseline levels 12 hours after refeeding.
A 2000 study found that a 3-day overfeed consisting of calories from carbohydrates led to a 28% increase in leptin levels, whereas a similar overfeed consisting primarily of calories from fat had no effect on leptin. [Dirlewanger M ., et al. Effects Of Short-Term Carbohydrate Or Fat Overfeeding On Energy Expenditure And Plasma Leptin Concentrations In Healthy Female Subjects. International Journal of Obesity Related Metabolism Disorders. November 2000, 24(11):1413-8.]
We can draw two inferences from these studies. First, that if we can reduce calories and properly time our refeeds, it’s likely that we can shed fat while keeping leptin levels elevated, and keeping our hunger under control. These refeeds should consist of more calories from normal, and the majority of those calories should come from carbohydrates. The trick is to not go too crazy too often.
The next question is how often should these “cheat meals” occur? To answer this question, there are many more variables to consider, such as how long you’ve been reducing calories and how low your body fat percentage. The longer you’ve been on your diet, and the lower your body fat percentage is – especially compared to equilibrium – the shorter the period needs to be between refeeds. In my experience, every 7 days between refeeds seems to work very well.
In a future post, I’ll come up with some rationale for determining time between refeeds, as well as talk about you can further optimize your leptin levels (and therefore fat loss) through carb cycling and strategic fasting.
Now I’d like to hear what you think. Do you agree? Disagree?
Hit me with your comments and questions below!
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