A PSA for those who might like to have less body fat: a number of observational and experimental studies find that the energy density of your diet (as in, calories per gram) is a very, very good predictor of ad libitum caloric intake. I doubt that an increase in the caloric density of our diets fully explains the obesity epidemic—there’s probably something to the “hyperpalatability” idea (though hyperpalatable foods are almost always very energy dense too), habitual nicotine and THC intake trends probably matter, I’d buy that some contaminants even if not lithium are causing people to be hungrier or less physically active, etc etc—but I find it implausible it’s not an important one, and even better, it’s one that you can calculate very easily for most of what you eat and then control with less effort than you’d have to expend for almost any other type of “diet”.
This is consistent with e.g. the potato diet being anecdotally weirdly effective at causing weight loss (~1 cal/gram which is pretty low), and also consistent with most of the generic conventional wisdom around diet like “eat more fruits and veggies and lean meats and less dessert and fast food”, and IMO makes lots of intuitive sense—satiety is complicated, but having a lot of stuff in your stomach is clearly pretty important, so, just put a lot of stuff in your stomach that doesn’t actually have many calories, lol.
having a lot of stuff in your stomach is clearly pretty important
A question I have here is, why not try for low calories per litre instead of (or as well as) low calories per gram?
Some thoughts on that:
The relevant thing would be density after chewing, not density on the plate. Maybe there’s not much variance in that. (If so, maybe “swallow your food without chewing” is an unrealized life hack for losing weight, with the caveat that it increases your risk of choking and dying.)
Maybe your stomach will break down less-dense contents faster? A very naive model says that if you compress something, its surface area decreases so there’s less for acid to react with but the same mass. So it’ll take longer to fully dissolve in an acid bath, but take up less volume initially. I don’t know which will take up more litre-seconds in total, or if that’s the right question to think about. Plus at some point things leave the stomach and I don’t know what triggers that.
How does this whole thing work with fluids? Presumably they leave your stomach quite fast, so per-calorie they should contribute less to satiety than solids?
> A question I have here is, why not try for low calories per litre instead of (or as well as) low calories per gram?
I think calories per gram is usually what people study due to some combination of: - this is the way somebody chose to measure “energy density” early on and it stuck for whatever reasons things stick - in cooking and/or conducting experiments, mass is pretty much always easier to measure than volume (even with liquids, in my opinion...) - we see this metric work pretty well—better than basically any other known single factor, is my impression—to predict satiety response, ad libitum caloric itake, diet adherence, and long-term weight changes in various experiments
I do know of a single-meal study that looked at how volumetric energy density (comparing potato chips vs. popcorn, which have similar energy per mass) predicted ad libitum caloric intake, and found that it does seem to independently matter. I don’t know of any other similar studies, though I won’t claim to be up to date on the literature.
>Plus at some point things leave the stomach and I don’t know what triggers that.
”gastric emptying” is the key term used in studies of this question (I haven’t really studied this myself)
>How does this whole thing work with fluids? Presumably they leave your stomach quite fast, so per-calorie they should contribute less to satiety than solids?
Right, that’s the usual finding. Drinking lots of water before or with meals does seem to promote satiety and lower ad libitum caloric intake, so water itself certainly counts for something, but liquids are generally nowhere near as filling per mass as solid foods, which agrees with the conventional wisdom around not drinking calories.
A PSA for those who might like to have less body fat: a number of observational and experimental studies find that the energy density of your diet (as in, calories per gram) is a very, very good predictor of ad libitum caloric intake. I doubt that an increase in the caloric density of our diets fully explains the obesity epidemic—there’s probably something to the “hyperpalatability” idea (though hyperpalatable foods are almost always very energy dense too), habitual nicotine and THC intake trends probably matter, I’d buy that some contaminants even if not lithium are causing people to be hungrier or less physically active, etc etc—but I find it implausible it’s not an important one, and even better, it’s one that you can calculate very easily for most of what you eat and then control with less effort than you’d have to expend for almost any other type of “diet”.
This is consistent with e.g. the potato diet being anecdotally weirdly effective at causing weight loss (~1 cal/gram which is pretty low), and also consistent with most of the generic conventional wisdom around diet like “eat more fruits and veggies and lean meats and less dessert and fast food”, and IMO makes lots of intuitive sense—satiety is complicated, but having a lot of stuff in your stomach is clearly pretty important, so, just put a lot of stuff in your stomach that doesn’t actually have many calories, lol.
A question I have here is, why not try for low calories per litre instead of (or as well as) low calories per gram?
Some thoughts on that:
The relevant thing would be density after chewing, not density on the plate. Maybe there’s not much variance in that. (If so, maybe “swallow your food without chewing” is an unrealized life hack for losing weight, with the caveat that it increases your risk of choking and dying.)
Maybe your stomach will break down less-dense contents faster? A very naive model says that if you compress something, its surface area decreases so there’s less for acid to react with but the same mass. So it’ll take longer to fully dissolve in an acid bath, but take up less volume initially. I don’t know which will take up more litre-seconds in total, or if that’s the right question to think about. Plus at some point things leave the stomach and I don’t know what triggers that.
How does this whole thing work with fluids? Presumably they leave your stomach quite fast, so per-calorie they should contribute less to satiety than solids?
> A question I have here is, why not try for low calories per litre instead of (or as well as) low calories per gram?
I think calories per gram is usually what people study due to some combination of:
- this is the way somebody chose to measure “energy density” early on and it stuck for whatever reasons things stick
- in cooking and/or conducting experiments, mass is pretty much always easier to measure than volume (even with liquids, in my opinion...)
- we see this metric work pretty well—better than basically any other known single factor, is my impression—to predict satiety response, ad libitum caloric itake, diet adherence, and long-term weight changes in various experiments
I do know of a single-meal study that looked at how volumetric energy density (comparing potato chips vs. popcorn, which have similar energy per mass) predicted ad libitum caloric intake, and found that it does seem to independently matter. I don’t know of any other similar studies, though I won’t claim to be up to date on the literature.
>Plus at some point things leave the stomach and I don’t know what triggers that.
”gastric emptying” is the key term used in studies of this question (I haven’t really studied this myself)
>How does this whole thing work with fluids? Presumably they leave your stomach quite fast, so per-calorie they should contribute less to satiety than solids?
Right, that’s the usual finding. Drinking lots of water before or with meals does seem to promote satiety and lower ad libitum caloric intake, so water itself certainly counts for something, but liquids are generally nowhere near as filling per mass as solid foods, which agrees with the conventional wisdom around not drinking calories.
Huh – I wonder if this has helped me since I made a concerted effort to eat leafy greens regularly (basically every day).
I always liked the ‘fact’ that celery has net-negative calories :)
I do also lean towards eating fruit raw versus, e.g. blended in a smoothy. Make-work for my gastrointestinal system!