alt Hacker NewsAdaptation in energy expenditure includes both metabolic adaptation as well as "NEAT" ("non-exercise activity thermogenesis"); the latter includes subconscious changes in posture, fidgeting, and various other things that can increase/decrease the body's energy expenditure by a massive degree, in an effort to (as far as people can tell) maintain a "set point" in the body that is difficult to change. This set point resists both weight gain and weight loss, both attempting to resist the change in the first place and attempting to undo it if successful.
I'm not suggesting that it's impossible to lose weight through sufficiently large caloric restriction. I'm observing that it is not anywhere close to as simple as "CICO", because CO is heavily a function of CI, rather than the popular incorrect perception of CO being things like "exercise".
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Neat can maybe explain a couple hundred kcal variance in most people, perhaps there are exceptions but 50%? I've never seen that in the literature.
Calories in calories out is just the summation of expenditure and intake, just because the body is complex and there are many interdependent factors doesn't mean it cant be resolved to a vector which determines weight gain/loss. The problem is people google a tdee calculator, get some scalar which is likely wrong, perhaps substantially, make lifestyle changes, and then have an expectation of some result in a specific timeline that isn't realistic, and then eat a bunch of sodium, put on 2 lbs in their "deficit", and think the diet made them fatter! Or they read that -3500kcal == -1lb fat, calculate their calories burned from the machines at the gym, and get frustrated when it doesn't work (I'm guilty!).
Weight loss is actually really hard because it really just requires a sustained effort over a long period of time to achieve anything. You might not see any results for weeks as your body adjusts, you get your diet locked in, etc. And since your weight can vary so much day to day, it's hard to stay motivated. Ozempic kind of bypasses these problems. You know what else works? 20k steps a day and eating on a backpacker budget :P
There is a wide gulf between “when you exercise your body saves calories elsewhere in the day…when you eat less your metabolism slows down” and “some people can’t lose weight on 50% calorie restriction.”
The former is very well supported in the literature. The latter is only supported in low quality studies like where people self report their diet.
The CICO hypothesis accounts for metabolism. Your weight is a function of CICO and time. You can track calories in, weight, and time. From there you derive calories out.
The problem isn’t that CICO is wrong, the problem is that it turns out actual caloric restriction over time is really really hard.
The current best advice for weight loss is to avoid highly palatable and/or calorie dense foods, prefer foods that are highly satiating and low in calories, and strength training helps. Do whatever cardio you need for heart health; more cardio is at best unnecessary and at worst demotivating because extra effort will not net extra results. Slow and steady is easier to stick to.
One problem is that even though small deficits lead to more long term success, small deficits are very hard to track, and very hard to stick to.
When the size of your calorie deficit is two tablespoons of ranch dressing and a cookie per day, it’s easy to blow past it without even realizing.
CICO isn’t a diet strategy. By itself it won’t help you lose weight any more than kinematic equations help you to throw a ball.
But it’s not wrong.