So, since this has come up a couple times here and there, I thought I’d post a topic here on it based on looking into this question.
It’s speculated (and seems to be taken as a fact in parts of the Internet) that solid food gives greater satiety than liquid food. The evidence I’ve found so far suggests this claim is inconclusive at best, and simply wrong at worst, with an in between possibility of ‘it depends on the type of liquid or solid food’ (with sugar showing a difference but protein not showing a difference between liquid and solid forms).
Some of the problem appears to be also confounded by the fact that a lot of the studies were only secondarily looking for satiety, but primarily or also looking at weight gain or loss.
But so, we’ll start with this survey of the evidence, though focused on weight change (it includes studies that also talk about satiety) :
What is the impact of liquids versus solid foods on energy intake and body weight?
Primary conclusion: There’s conflicting results.
A more direct experiment:
Effect of drinking compared with eating sugars or whey protein on short-term appetite and food intake
This is an interesting and telling one, as the results indicated there was a potential difference, with greater satiety for solid food, when considering sweets. However, there was not a difference for satiety when considering protein (specifically whey protein). And the final conclusion suggested macronutrients play a bigger role on satiety than liquid vs solid (which, we should all here know that the macros change satiety a lot).
One that looked at just primarily sugar solid vs liquid food:
No difference in satiety or in subsequent energy intakes between a beverage and a solid food
The title gives that one away. No difference was found with both types being high in sugar and fat free.
And, not itself much of a study, but here is something in favor of the idea that there is a difference and some explanations provided for the idea, with some citations you can easily look up for the actual studies:
The Diet Dilemma: Cut Liquid or Solid Calories
Though, again, they are primarily considering weight, not satiety, it still factors in.
Some critiques I’ll note of the studies included in that, the experiment where they compared jelly-bean consumption to soda didn’t have proper controls or test the reverse setup. What they did is give people a bunch of jelly beans for a month, let them return to whatever their normal diet is for a month, and then gave them soda for a month and compared. They didn’t do another group that did soda first for a month, did their “normal” for a month, and then did jelly beans for a month. Something else to note: while both foods gain all their calories from carbs, 100% (or near) of the carbs in soda are from Sugar (High Fructose Corn Syrup usually, sometimes Sucrose, though that wasn’t specified), whereas jelly beans are high in sugar, they are not 100% sugar.
When comparing Coca-Cola to Russell Stover Jelly Beans (simply the easiest two things to find, other sodas and jelly beans may very a bit but should be fairly consistent with this point), we find that for the same 140 calories from 38 grams of Carbohydrate each, Coca-Cola has 38 grams of sugars while Jelly Beans have 34. Very close, yes, but not the same
If you look on the sides of the jelly Beans link, you’ll find other brands, most of which actually show a lower percentage of sugar to total carbs compared to the one I selected (and one that shows more sugar than total carbs, so I’d ignore that one).
Unfortunately, I haven’t yet found what’s in the jelly beans completely. Probably a lot of HFCS, but could also be other kinds of sugar that may or may not have higher proportions of Fructose to Glucose, which can make a difference as well (a topic for another post, perhaps, if others haven’t already done that one).
The next study mentioned in the link looked at a lot of factors and concluded more weight loss was found from cutting out liquid calories than solid calories, but it even noted that this was not found, or not found as profoundly, when milk was cut out as opposed to soda and coffee with sugar, and it appears they probably didn’t look at equivalent macros between the liquids and the solids.
It goes on to explain several of the believed possible mechanism, which include factors that again don’t have to do with the foods being liquid vs solid in themselves, but rather factors that come along with those states for most foods (fiber being a big one to me when looking at solid fruit vs liquid, but they note some other possibilities).
Alright, so there’s that from me, share other research for or against the idea.