Chemically, a calorie is a calorie. But one calorie of fat is metabolically different from the equivalent caloric value of protein, because food is not processed by the body the same way that a calorie is measured.
Literally no amount of hand wringing will change that fact
Examples like yours focus heavily on the "calories in", but forget to consider the "calories out" aspect. What I mean there is, when someone says that the body processes different macronutriets differently, a lot of that has to do with how it affects "calories out"
If you eat 500 calories of a food that your body will only process a small amount of, and expel the other 450 calories as waste, that 450 is part of the "calories out". That's only a net "calories in" of 50.
On the other hand, if you eat 500 calories of a food that your body chooses to process/store most of, that's 400 calories in, and only 100 calories out.
The calories out part of the equation isn't just the energy you expend per day through movement/metabolic processes/etc, it's also the calories that are expelled as waste because the body didn't store that macronutrient.
Does this much lack of absorption ever actually happen, though, outside of exceptional cases like if you get food poisoning?
Carbohydrates decrease insulin sensitivity more than protein and unsaturated fats would. Decreased insulin sensitivity means increased insulin resistance.
"Having insulin resistance means that the walls of the cells within the body that need to take in glucose for energy, have a much-lowered sensitivity to insulin. This makes it harder for the cells to receive the necessary glucose through the cell wall.
That glucose then remains in the bloodstream, resulting in high blood sugar levels, which the liver then has to manage. When this excess sugar reaches the liver, it is converted to fat. The fat cells leave the liver via the bloodstream and cause weight gain. If left unmanaged this can lead to obesity."
> it is important to understand exactly what it is meant by "a calorie is a calorie." The most common meaning is that is it impossible for two isocaloric diets to lead to different weight loss.
I think that is hyperbolic - I've never heard that all isocaloric diets are guaranteed to result in the exact same weightloss. The point of "a calorie is a calorie" is that you need to reduce calories to lose weight.
From the chart in the article, going from a 10% carb diet to a 50% carb diet (which is a huge change) only results in a effective caloric difference of ~130. It is _much_ simpler and more effective to just skip a 100 cal snack than it is to cut all carbs out of your diet.
In my experience all large quantities of food increase hunger because you get your body used it. With carbs it's just easier to eat more in a smaller amount of space.
To simplify the body approximates the food in your diet, but also measures the amount of fat you have. A great many things trick the first, but the second doesn’t care what or when you eat. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6039924/
Ironically, you demonstrate this in your last paragraph. If all calories are the same, yeah, just cut 100 out some other way. But if they have different effects on hormones, satiety, any number of other systems, then it may not be "simpler and more effective" to "just" drop 100 calories as a snack. You may need to actually change what you eat.
I'm currently on a lazy keto diet and am down 33 pounds. I know it's only one data point, but it definitely seems easier than other diets I've tried.
[1] https://www.hsph.harvard.edu/nutritionsource/2018/11/27/effe...
Maybe that's true evolutionarily over tens of millions of years, but it's definitely not true that cellulose calories are remotely equivalent to fat calories -- not unless you're already a ruminant, anyway. Similar issues may present themselves with other types of calories. Just because in theory we could evolve to optimally use all potential sources of energy in food doesn't mean that we actually have yet.
Whole system is rather complicated process and don't exactly simplify to equalling same energy you get from burning or is stored in chemical bonds...
I had this very argument with an MD who was trying to tell me that if you operate at a sustained caloric deficit you'll eventually stop losing weight.
On some level, CICO must be true. Famine is a thing. If you consume a very small but still nonzero amount of calories you will eventually die. So it's not correct to say that "CICO is BS" or anything similar.
Whether CICO is an effective way of sustainable weight loss is another conversation.
Depending on the definition of "sustained" (I assume the MD meant sustained absolute calories per day, not sustained calories below metabolism) it could be true, because as your body shrinks it reduces its metabolism partly because there is simply less of it.
and on the flip side, the amount of energy you absorb varies by the type of molecule the body is metabolizing, and also the leading indicators are that the gut microbiome plays a huge amount in determining how much energy the body absorbs. Two people can absorb several hundred calories' difference from eating the same diet and the same quantity, and over a scale of a week+ that turns into pounds gained or lost.
"CICO" is a massive oversimplification of an incredibly complex set of chemical processes. Like yes obviously your body cannot violate the laws of thermodynamics but we've just agreed that two different people will neither take in nor burn out the same amount of calories from doing the exact same things! Again, two people could eat the exact same things in the same amounts and exercise the same amount, and potentially gain a pound every week while another person holds weight.
And the problem is that this oversimplified advice gets translated into oversimplified medical recommendations/etc, and an incredible amount of moral opprobium. Fat people are an easily visible target and are systematically discriminated against - they are paid less, they have worse interpersonal outcomes, and they receive worse medical care. The first answer of a doctor to a fat person is always "lose weight" - I have a relative whose complaints were ignored until she finally had a volleyball sized ovarian tumor removed in a hysterectomy - and that goes doubly for women in general, whose medical complaints are downplayed/ignored in general.
And - not that it matters - but fat people have lower lifetime health spending. They're not "costing you" anything, not that that is ever a good reason to abuse a group of people, but our healthcare spending is hugely back-loaded towards end-of-life care, the third knee replacement and the two weeks in the hospital with congestive lung failure, all tend to be avoided by fat people. They die early and don't incur those expenses.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2225430/
On a personal level, "what can I do to improve my own health", yes, the answer is correct that for your own personal metabolism the only thing you can do is to reduce your caloric intake. But everything past that, we're gradually realizing it's been horribly oversimplified by this idea that humans are the same as a blast calorimeter. It certainly doesn't apply on population-wide scales, there have pretty obviously been dietary shifts (massive increases in consumption of HFCS and other processed sugars) and potentially microbiome or hormonal shifts due to chemical exposure that have compounded these issues and exacerbated the decrease in activity. And that is certainly obscured (and attempts to study and remediate it stymied) by the "just eat less than you burn bro!" that is so popular.
When you want/need to loose, say, >40 pounds it would be plausible that an error of 200-300 calories doesn't matter as much because most likely your excess intake is beyond that.
Your health would improve considerably by following the simple but inaccurate model instead of doing nothing.
As your weight goes down CICO becomes less and less useful and you need to switch to a more accurate model.
I'm not an expert and can only talk from personal experience (aka unscientific anecdotes) of me and my social circle.
It can be true. Your body tries to maintain homeostasis and can adjust your base metabolic rate. Just like if you hyperventilate, your blood pH will be maintained by buffering until you exceed the buffering capacity (co2).
If you drop your calories low enough, of course, you will continue to lose weight.
> So it's not correct to say that "CICO is BS" or anything similar.
It is BS if you are able to show different amounts of calorie utilization under different diets. I didn't realize the difference was close to 300 Calories though.
Also, some calorie-deficient diets result in a higher average degree of hunger than others with equal caloric input. Some high carb diets produce insulin spikes and subsequent hypoglycemia and hunger pangs.
And some calorie-deficient diets result in different muscle/fat loss ratios than others.
Finally, not all exercise activities have the same effect on body composition. Long slow distance promotes a lean body, but it's not for everyone.
If someone wants to lose weight, a simple (though not necessarily easy to execute) plan is to calculate their rough current TDEE, then eat those amount of calories minus 300 or so, and if they're not losing weight, do 200 calories less than that. Rinse and repeat.
If someone follows the above protocol, and we take as a given they stick to it, do you agree that they'd lose weight?
In practice, other diets can be easier to adhere to, for various reasons:
1. Eating at a caloric deficit makes you hungry, which makes it harder to not overeat.
2. People are bad at counting calories, so might get wrong numbers.
3. It's not fun to count calories, so people might not do it.
In many ways, something like keto that works for a lot of people without the annoyance of counting calories, can be much better for many people.
But in terms of the underlying mechanics, it's still a calorie deficit that is producing those results, which might give more flexibility to people who do want to count calories. (E.g. for me, counting calories was way better than any other "diet" I tried - I could keep eating what I wanted, so was able to be very flexible with my "diet" while still losing weight).
You may not realize the influence the "alternative" advice has. For many years I was confused on this, thinking that it's not as simple as CICO, that fasting and/or reducing carbs somehow did something special, etc.
In the last year, I started taking weight loss more seriously, I bought into CICO, started calorie counting, and lost a bunch of weight (though to be clear, I wasnt obese, just a bit overweight).
And since then, I've often thought to myself that maybe I'm misremembering exactly what I thought before, that surely I didn't really think that CICO isn't true. But I've had the opportunity since to talk to many people about this, most of them adamant that I couldn't have lost weight without giving up carbs, or that they could lose weight just by reducing carbs without any thought to total calories, or other other such things.
And this alternative cute of "the experts in this field are wrong, only I an outsider can see the obvious truth that somehow vaguely you don't need to worry about calories at all" causes real harm, both to what People do, and to how they think.
If someone wants to lose weight and is willing to actually put in some effort, imo the best thing to do is to count calories, reduce intake, and find out what set of foods Keeps you full and happy within that caloric window (quite possibly keto being the best option for a lot of people).
... also I'd like to know how to get it to start doing that again. (yeah, yeah, I'm sure the answer is "take T and HGH, they're basically magic, aside from all the other health problems they give you")