> "This idea of 'a calorie in and a calorie out' when it comes to weight loss is not only antiquated, it's just wrong," says Dr. Fatima Cody Stanford, an obesity specialist and assistant professor of medicine and pediatrics at Harvard Medical School. The truth is that even careful calorie calculations don't always yield uniform results. How your body burns calories depends on a number of factors, including the type of food you eat, your body's metabolism, and even the type of organisms living in your gut. You can eat the exact same number of calories as someone else, yet have very different outcomes when it comes to your weight.
This is just plain dishonest writing. Just because there are other variables, or that different people burn different amount of calories, does not make 'calorie in and calorie out' wrong. If John burns 2000 calories a day and has different organisms in his gut from Sarah who burns 1500 calories a day, in no way disproves calories in / calorie out. All it proves is that people are different, a premise that the modern science community seems to find a challenging notion.
The theoretical concept of CICO is thermodynamics and indisputable, but the point that the data demonstrates and that these Harvard scientists are discussing is that all of the parts of the equation are so error-ridden and faulty that to combine them together in practice is not effective. Everything from the faulty results of burning food in a calorimeter, to users guesstimating the ingredients in food they cook, to the wide amount of false data inputted to calorie tracking apps, to the extremely complex and still not well understood G.I. tract, to measuring how much each individual can absorb, to how much cooking effects it, to how much the personal biomes between gut and colon play an effect, etc all add up to the reality that there is too much error to pretend the system is useful.
If using the system got you to eat differently, and eating different made you lose weight, then congratulations, but that doesn't prove that the food you ate was actually X calories or that you actually burned Y calories, and that that deficit is why you lost weight, nor does it mean that someone else who ate as much as you did would have their body change in that way.
Note the caveat in your quote. It's not that calorie in/out is theoretically wrong, it's that it is an unhelpful/antiquated strategy "whenitcomestoweightloss".
First, note that the calorie estimates on food packaging can be off, sometimes by as much as 25%.[1] Restaurant foods have an even wider discrepancy. [2] And as you point out, different people will digest them and absorb different nutrients from the same food making comparisons difficult. For example, I absorb a small fraction of the calories from dairy products because they unfortunately pass through my digestive system quickly and remain largely undigested.
And as others have noted, accurately estimating calorie expenditure can also be difficult without professional equipment, so in practice measurements of calories expenditure can be off by a significant margin as well.
Combining all of these sources of error can result in excessively wide error bars. Someone who relies on calorie in/out estimates to dictate their consumption may end up eating significantly more or less than is optimal.
Of course, even if counting calories in/out is wildly inaccurate it might still have a positive effect if it causes people to be more aware of the food they eat. Unfortunately I'm not aware of research that teaching people to count calories results in better health outcomes than other diet strategies. (Though it does seem to increase people's odds of developing eating disorders. [3])
It's one of those cases where the theory may be correct in theory but that doesn't make it particularly useful in practice.
The fact that counting calories is difficult, or that some food labels might be wrong, is not evidence that CICO is incorrect. Just as the fact that different people burn different amounts of energy does not disprove CICO.
I'm astonished how many commenters are desperately trying to find loopholes in simple laws of physics.
I said above, it's not that CICO is wrong. No point I have raised could possibly disprove CICO because CICO is obviously correct from a physics perspective, and I'm not sure if anyone here is trying to find loopholes in simple laws of physics.
I (and most of the other commenters here it seems) keep trying to communicate that it is possible to be both technically correct and simultaneously not useful as a weight loss strategy.
CICO isn't about counting calories, all you have to do is to gradually eat less until you start losing or maintaining the weight you want. CICO guarantees that to work, and lots of people have used that strategy to lose weight, it works 100% of the time if you follow it properly.
It wont work for everyone though, since many people can't make themselves eat less without following some rituals, the problem there isn't CICO but that those people can't implement a CICO diet properly. But that doesn't mean that CICO is a useless concept for losing weight, it just means that those people needs more help to keep their psychology in check.
Saying that CICO isn't useful when CICO is the basis for every single weightless diet in existence is just ignorance or a lie. All weightless diets either makes you absorb less calories by some method, or make you burn more calories, so the first thing when looking at a diet is asking how it relates to CICO. Trying to sweep that under the rug as some old school nonsense principle that has proven to not work just proves how much nonsense there is in nutritional "science".
CICO has limited use. Boiling everything down to a single physics based metric doesn't give us all the information we need.
Knowing what mechanisms and processees go into losing weight can make the journey much more intellectually stimulating, satsifying for the participant and smooth out incredibly rough bumps in the road to losing weight. CICO can't fill this need for tailoring weight loss to smooth out the efficiency losses you get with brutal cuts into one's life and psyche.
Pumping out a single metric and hammering flat all the differences in personal process with psychology and ritual screams of unnecessary suffering. It's probably wrong to use oneself like that.
Very few people live according to the physics based description of what their life should be... However one would derive that idea without hiding or ignoring personal presuppositions?
The "CICO diet" most here are referring to is when people attempt to estimate their "calories in" and their "calories out" and keep the former slightly lower than the latter. To my knowledge this has not been demonstrated to be generally effective, possibly due to the challenges with estimating these values with a reasonable degree of accuracy.
If you're simply referring to the physics of CICO that underpin most diets then I have already acknowledged it is correct.
But being correct does not make it necessary knowledge for people looking to lose weight any more than Hamiltonian mechanics is necessary knowledge to play tennis.
If I still haven't managed to convey the distinction between technical correctness and practical utility yet then I have to conclude this is a gap I cannot bridge and I wish you luck.
I think you are missing their point. Calories in and out is a piece of the puzzle and net calories is often not enough to make a good prediction. Two similar people can consume precisely the same number of calories and have the same level of physical fitness and physical activity and have different outcomes.
People are indeed different and the scientist you quote is saying precisely that.
Calories in vs out is wrong because those who tote it assumes that only physical exercise has an effect on calories "out". New research shows that the human body is keenly aware of the amount of energy available and adjusts many bodily functions (tissue repair, heat, hair growth, immune defense, etc) accordingly. This is why just restricting calories in and exercising more won't necessarily mean you loose weight.
Taken literally calories in vs out is of course true.
> Calories in vs out is wrong because those who tote it assumes that only physical exercise has an effect on calories "out".
No, they actually dont assume that only physical exercise has an effect on calories burned. In fact, CICO is agnostic to the means by which calories are burned.
> This is why just restricting calories in and exercising more won't necessarily mean you loose weight.
Actually, so long as you burn more energy than you consume, you will lose weight. Again this is agnostic to how the energy is burned. What the body does to adjust is merely effecting the amount of energy burned. It does not effect the formula concerning CICO.
> Two similar people can consume precisely the same number of calories and have the same level of physical fitness and physical activity and have different outcomes.
You are trying to find a loophole here that doesn't exist. If two people burn the same amount of energy E_O ("out") and take in the same amount of energy E_I ("in") with E_I < E_O, then both of them must take those calories from somewhere else in their body and must therefore undergo weight loss. There is no way around that.
Now, notably you didn't specify E_O, you only said
> the same level of physical fitness and physical activity
which can mean a lot of things.
All the supposed loopholes work in exactly the same way: It might not be entirely clear what the values of E_I and E_O are, so "calories in, calories out must be wrong". (Which, again, is impossible because it's just conservation of energy, i.e. a law of physics.)
In any case, just like you can bound E_I from above by counting calories, there are ways to constrain E_O from below: If both people have the same mass (say 100kg) and walk up the staircase in one of the towers of Cologne cathedral (~150m), then they will both have spent at least E_O >= 100kg * 150m * 10m/s² = 150,000 J.
How can you possibly read GP's comment and think they don't realize this? Stop nitpicking. Calories In vs Calories Out is correct. Period. It doesn't matter if Calories out is hard to calculate.
Calories In vs Calories Out is mediated by a factor, usually labeled S, which accounts for the individuals own metabolic factor.
Meaning if you are naively doing calories in vs calories out, or doing desired estimated calories out based on a table, you have an error factor significant enough to skew your results.
What we call it doesn't matter, but what GP said is actually incorrect as written.
> What we call it doesn't matter, but what GP said is actually incorrect as written.
Please do point out which part of my comment is incorrect.
> Meaning if you are naively doing calories in vs calories out, or doing desired estimated calories out based on a table, you have an error factor significant enough to skew your results.
What does "naively doing calories in vs calories out" mean exactly? I agree that some people do it naively but where exactly was my comment naive?
> Calories In vs Calories Out is mediated by a factor, usually labeled S, which accounts for the individuals own metabolic factor.
Yes, the metabolic factor affects the numeric value of E_I and E_O (I never disputed that), but once you have determined their value (or bounded them as in my comment – which, as demonstrated, is orders of magnitude easier), the statement "weight loss occurs if E_O > E_I" remains correct.
"Calories In vs Calories Out is correct". Maybe it’s correct but I doubt it’s useful. How do you explain that people who do not count calories maintain their weight ?
Maybe, but in this case I don't think it's fallacious. She publishes, is cited all over the place, teaches at a well regarded school, and has explicitly and plainly said CICO is wrong when it comes to weight loss.
This[1] is a good summary of a talk she gave about a year ago and in it she talks a bit about the non-CICO factors in weight gain or loss. Here's one example:
“The gut microbiota of those that are lean versus those that have obesity are quite different, so much so that we can often take the gut microbiota out of individuals that are lean and place it in those that have obesity and see weight shifts with no other modifications."
> She is the director of diversity and inclusion for the Nutrition Obesity Research Center at Harvard (NORCH)
Why did I know this before I even looked?
>“The gut microbiota of those that are lean versus those that have obesity are quite different, so much so that we can often take the gut microbiota out of individuals that are lean and place it in those that have obesity and see weight shifts with no other modifications."
Yeah, so all that effects is CO (calories burned). This does not disprove CICO. I see Fatima has a limited grasp of logic.
Where in my comment did I use or refer to the resting burn rate? This is precisely the point: If you can bound the total calories burned (E_O) from below (by means of the laws of physics), individual variations of metabolism don't matter – the calories must have been burnt by the person in question no matter what.
it's not that the values E_I and E_O might not be clear, it's most certainly not clear and surely not easy to estimate for people trying to lose weight
CICO is a great model for 3rd parties in your diet. If you have someone watching your dietary intake, they can count calories for you and you will succeed at losing weight nearly 100% of the time if they can monitor everything you eat. Most individuals cannot count calories even reasonably close to what they are consuming due to a number of factors.
The model is also an abject failure when it comes to the individual psychology of overeating. This is where people like the above doctor says it's "just wrong". CICO as the only method of weight loss is about as effective as quitting smoking cold turkey (3 to 5% success rate). In general getting people to stop eating high caloric density / high glycemic index foods and replacing them with something else is a good starting point. You're effectively lowering the CI but not requiring a cutoff point for the individual.
when they said CICO is "just wrong" they should have said "just different for every person". My wife listens to a pretty entertaining podcast called Maintenance Phase and they did an episode on CICO where they basically call it BS because of all the other variables. I have a hard time dealing with CICO being wrong because I just don't see getting around the physics. In my mind, what's missed in CICO is the numbers and measurements are different for each person. A calorie limit for one person that results in weightloss may not work for someone else. It seems pretty obvious to me that calorie counting has to be done on an individual level and has to be done accurately ( a whole other problem ) but that seems to be missed on a lot of people.
EDIT: i wanted to mention something someone downthread hit on and that was also in the Maintenance Phase episode. Calorie burn is not constant and your body will adjust, so for you to effectively count calories and stay below some threshold you have to track what your body is burning as it adjusts which is probably very difficult.
I actually suspect CICO being wrong or right is actually bikeshedding technicality. The question is "Is CICO helpful to yell at a fat person?" and not in the technically if you can control every facet of a person's life they will lose weight under CICO, but whether or not a regular busy obese person potentially with health barriers, children, a full time job, and whatever other issues would find statistical use in it or is it just something that makes sense for thin people to yell about because its technically correct.
Lots of people just need to think in terms of CICO and no dumb diets to lose weight, they just eat less. Other people need to create arbitrary rules to eat less calories since they are addicted to some foods, so they need to cut out all the foods they are addicted to in order to reduce calories in. For example, people addicted to carbs do low carb diets to curb their calories in, people addicted to desserts do a no dessert diet and they will lose weight etc.
The only thin that makes this complicated at scale is that different people are addicted to different foods, so need to cut out different things to start losing weight. But CICO is the basis for all of those.
The duo on that podcast asserts gems like: we don't actually know if being fat is bad for you. Worth a chuckle.
I can imagine the podcast took off because people are hungry (pun unintentional) for something that validates inaction on improving their bodies. That show treats any sort of ambition about one's body as an eating disorder or unrealistic goal.
I know this is late but I was going back through my comments and found yours. Yeah , i have problems with the podcast on those terms too. I get their point that fat-shaming is harmful and I totally agree however, if someone is overweight then it's very much a good idea to try and reduce weight and not just consider it normal and healthy like the podcast sometimes implies. Granted, overweight people are a favorite prey for every charlatan out there and i feel like the podcast does an acceptable (but not perfect) job of calling them out.
oh and we (my wife and I) found the Maintenance Phase podcast by following Michael Hobbes from You're Wrong About which is another entertaining podcast. I don't always agree with his politics but if I ever met him i'd shake his hand, he does a really good job.
This is just plain dishonest writing. Just because there are other variables, or that different people burn different amount of calories, does not make 'calorie in and calorie out' wrong. If John burns 2000 calories a day and has different organisms in his gut from Sarah who burns 1500 calories a day, in no way disproves calories in / calorie out. All it proves is that people are different, a premise that the modern science community seems to find a challenging notion.