Dear Lyle,
I’ve been following a good fat loss diet for about 5 weeks now and was losing fat consistently. But now I’ve hit a plateau and I can’t lose any more fat. What causes the plateau and how can I get my fat loss started again?
To be absolutely honest, no one has all the answers to what causes fat loss to plateau. Various mechanisms have been suggested including a drop in thyroid levels, or increased leptin or decreased catecholamine levels. While it’s academically interesting to wonder exactly why the body tries to attenuate fat loss by lowering metabolism, from a purely practical standpoint, it’s not that critical. Simply accept that fat loss plateaus happen and worry less about what causes them and more about what you can do about it. In general terms, we can say that a fat loss plateau occurs when metabolic rate slows to such a point that the caloric deficit you’re creating (through some combination of caloric restriction and increased activity) is canceled out. The most common approach to breaking fat loss plateaus is to either decrease calories even more or increase activity. Both of which serve to create a further caloric deficit, spurring more fat loss. But there’s a limit to how little you can eat or how much you can increase activity to compensate. Additionally, it seems that the lower your calories go (or the more activity you do) the more muscle and less fat you tend to lose. To this approach is ultimately a dead end. The second, and my preferred approach, is to take 5-7 days off your diet. While this runs totally counter intuitive to what dieters have been taught (‘Eat MORE to lose fat’) it does work. Giving your body a break from dieting for even a short period of time tends to upregulate metabolism enough that going back to your diet for a few more weeks will spur some further fat loss. My current recommendations (assuming you don’t have a specific time frame to get to a certain bodyfat levels) are to diet no more than 4 weeks straight before taking a week off. 4 weeks just seems to be the time point when the body really starts to adjust metabolism downwards and fat loss tends to slow. So this is the time to take a break from your diet. When you do break from your diet, go back to eating roughly maintenance calories and normal carbohydrates (especially if you’ve been lowcarb dieting). For whatever reasons, this seems to really help the body get past fat loss plateaus. And as long as you continue training intensely, it’s rare to put on a really significant amount of bodyfat during this 5-7 day span. But you will refill muscle glycogen (see previous question) and you might even rebuild any muscle you may have lost during your previous 4 weeks of dieting. I find that I tend to lean out even further during the week that I’m off of the Cyclical Ketogenic Diet (CKD). Whether it’s just filling out my muscles or my body continuing to use fat for fuel or the thermic effect of all those carbohydrates, I don’t honestly know. But it does work.
About the author
Lyle McDonald+ is the author of the Ketogenic Diet as well as the Rapid Fat Loss Handbook and the Guide to Flexible Dieting. He has been interested in all aspects of human performance physiology since becoming involved in competitive sports as a teenager. Pursuing a degree in Physiological Sciences from UCLA, he has devoted nearly 20 years of his life to studying human physiology and the science, art and practice of human performance, muscle gain, fat loss and body recomposition.