"Spike Day" Nonsense

The concept of the benefits of a “Spike Day” centers around the notion that leptin is a key hormone in bodyweight regulation, and that leptin decreases in response to dieting, which causes our weight loss to slow down. Thus, by having a day of overfeeding, the thinking goes, we can bring leptin back up to baseline, thereby “side stepping” the decrease in leptin that hinders our fat loss efforts.

The problem with this logic is that it misses a key part of the puzzle. First, a little background.
Without getting too technical here, Leptin is the hormone that is in charge of bodyweight regulation. When calories go up, stored bodyfat goes up, Leptin goes up. The result is you feel less hungry, metabolism goes up, etc. Essentially leptin tells the body that it is “well fed.” (So why do people get obese? Chronically elevated leptin = leptin resistance = leptin can’t do it’s job. Sucks, huh?) When calories go down, leptin drops, and you feel more hungry, and you want to eat more, metabolic slow down, etc. Basically, what’s going on here is that your body “fights against” weight loss, and one of the tools that’s used is leptin. (we all wish it fought just as hard against weight gain).

^^^Again, keep in mind, this is terribly oversimplified for the purposes of background info^^^

So then, along comes the Spike Day. By overfeeding once per week, they claim, you raise leptin, so you’re not dealing with the metabolic slowdown and other things that come along with a drop in leptin. Not so fast.

As I mentioned earlier, this is missing a key part of the puzzle. *Drum roll* Leptin basically rises and falls as soon as calories go up and down. The research has shown that it only takes about 24 hours for leptin to response to a calorie deficit or surplus:

http://jcem.endojournals.org/content/85/8/2685.short
http://www.ncbi.nlm.nih.gov/pubmed/8866554

What I’m saying here is that the Spike Diet has it only half right. Leptin does increase and decrease in response to calorie intake, but it responds rapidly. So raising it for 24 hours won’t do squat. As soon as your reefed is over, it goes right back down to where it was.

I do believe that a “cheat day” has other benefits, however, for most folks, the benefits are purely psychological. I’m not diminishing the importance of psychological tolerance of a diet, I’m simply saying that physiological arguments for the Spike Day don’t hold water; if you want to do a Spike Day because you enjoy it and it “works for you,” by all means, have at it.

One final note on Leptin. What I wrote above may beg the question “so how does anybody lose weight?” Or, you might say “see, I told you starvation mode was real!” When I talk about your body fighting against weight loss, you body can only fight so hard. You can always overcome it by eating a little less/moving a little more when weight loss slows.

Finally, like a Baptist Preacher, I’m going to conclude for a third time. There is something to the notion of taking break from your diet to regulate metabolism, etc. This is best accomplished by a week (or two) long “diet break” where calories are raised to maintenance level.