laying out the math

In case you're one of my many readers who see an embedded video and don't bother to click on it, let me lay out, in my own words, the case against CICO (calories in, calories out) made by Dr. Sten Ekberg. Ekberg's argument is a great reductio ad absurdum. 

Follow along as I paraphrase.

In CICO, the idea is that, if you expend more calories than you consume, you will lose weight. This is logical to a point. If, for example, you took in no calories at all for several weeks, you'd likely starve to death. To that extent, CICO is definitely a thing. But in practice, people will tell you that a pound of fat is equivalent to about 3,500 calories, so if you were to figure out our basal metabolic rate (BMR), then eat 500 calories under that BMR every day, you'd lose a pound of fat in seven days. Seems pretty straightforward, right?

But, Ekberg says, what if you continued on that path for 1,400 days (200 weeks)? Then according to the math, if you were a 200-pound man, you'd be down to a weight of zero because you'd be losing a pound a week. Is that really what would happen if you ate at a 500-calorie deficit for nearly four years? Of course it isn't.*

To me, this is a knockdown argument. CICO works to some extent, but it's obviously not the whole story. If you eat at a 500-calorie deficit for four years, not only will you still be around, you'll likely be healthier and more vigorous than ever before! This dovetails with my own experience last year: on the Newcastle diet, I was (well, ideally) eating no more than 800 calories per day. And while weight loss was precipitous at the beginning of my ten-week period, it began to level out in the final few weeks, with weight loss becoming harder and harder to achieve.

So this isn't to say CICO is bullshit. It's not. But it's not the whole story, and Ekberg's argument shows the limits of CICO thinking. This is where CIM (the carbohydrate-insulin model) thinking can supplement CICO: at some point, you have to differentiate weight loss and fat loss, and CIM concentrates almost exclusively on fat loss. CIM thinking takes us in the low-carb direction. While there's plenty of debate as to whether it's healthy to cut all carbs out of one's diet, the major thrust of most CIM-based diets today is the same: eliminate all processed carbs from one's diet. The closer you get to eating something that's still in its original state, the better. This is obviously painful news for those of us who love our breads and pastas, etc., but most modern diets will (grudgingly) allow for things like cheat meals or cheat days, so there's still room for a little indulgence.

And there we go—that's the mathematical absurdity of extreme CICO in a nutshell. My thanks to Dr. Ekberg for laying the matter out so clearly.

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*I can see some smartass retorting that CICO applies only to fat loss, so once you lose all your fat, the math for CICO no longer applies. Okay, genius, but can a human survive on zero body fat? Yeah... chew on that. You basically run into the same problem, just earlier.