I'm not a super big fan of this channel but at least on the surface the research they cite sounds fairly solid:
https://www.youtube.com/watch?v=x0JiwzwBEgEBasically describes metabolism in relation to fasting vs. small meals throughout the day.
Their takeway is: a couple large meals during the day in effect results in a higher resting metabolic rate than eating small but consistently throughout the day. When you eat, your blood sugar spikes and your body releases insulin which then stores carbs and fats as fat. After about 4 hours, your insulin levels fall and your body releases glucagon, which allows your fat cells to release that stored energy for use in your body. (Turning fats in to free floating fatty acids ready for transport to where they're needed, for example, rather than staying as stored fat.)
When you eat throughout the day, your insulin levels stay elevated. Meaning your body is in "store this shit mode" for a longer period of time, and not reaching the insulin levels required to trigger the release of glucagon and enter "release this shit" mode. While the channel isn't saying you can't lose weight doing the small meals thing, they posit you lose weight faster with a fasting-like eating schedule. The old thinking I always used to hear was "being in a fasting state convinces your body to store everything as fat because it thinks you can't get sustenance and thinks it must store everything you eat as fat, expecting a long period of deprivation to be incoming." Which this channel posits is not the case at all: being in a fasting state convinces your body it must release all its stored energy reserves because it's not getting anything new in and needs to get energy from somewhere, i.e. its emergency reserves, i.e yo fat ass.
On the other side of the coin, I'm guessing the non-fasting, small meal crowd would say that their insulin doesn't spike as hard if they eat consistently throughout the day, resulting in a lower overall conversion rate of carbohydrates and fat to fatty tissue, whereas I'm guessing the fasting group experiences two fairly big insulin spikes during the day, and a higher rate of conversion during those periods.
So I imagine it looks like this, using myself as an example:
I'd only eat two meals a day. And those two meals would be around 1200 to 1500 calories of stuff high in fats and carbohydrates. So I was likely storing a large portion of my meals, already rich in carbs and fats, as fat, at a faster rate because I was doing a mild fast and my blood sugar spikes were much higher. And while my resting metabolic rate would be higher a couple hours later because my insulin levels would fall and I wouldn't raise them back up by eating more, triggering the release of glucagon and ridding myself of fat.....because I was packing on so much fat due to what I was eating (combined with no physical activity to help burn it off) I was building up a surplus of fat even though my body was trying its damnedest to get rid of it.
Compared to the small meal folks....who, generally speaking, are probably eating fairly healthy if they're mindful enough to spread out their eating, I was probably gaining more weight even on a fasting schedule. So while the small meal group's insulin levels overall are higher throughout the day, they're probably consuming less stuff that the body tries to store as fat. They eat a balanced diet of mostly proteins and veggies with a little bit of carbs and some fat through out the day, meaning while they're more often storing what they eat as fat....they're storing less of it than me, who was cramming down tons of calories and carbs all in one shot while having highly elevated levels of insulin.
So in summation.....I think it's less about
how you eat and (obviously) much more about
what you eat. If you're eating a lot of carbs and fats, whether that's in two (or one) large meals during the day, or consistently in smaller portions throughout the day.....it all will end up as fat regardless. Fasting might allow you to release some of that fat a little faster than a normal eating pattern or a spread out eating pattern, but you'll still pack on the fat regardless. And if you're eating smaller portions more consistently....but it's still largely made up of carbs and fat.....you're still going to be storing that food as fat and you'll probably release it more slowly than people that are doing some kind of fasting.
(Mind you, this is only in relation to eating and your metabolic rate without factoring exercise in.)