Beans like chickpeas and lentils, or grains like quinoa, have some carbs, but a lot more fiber. Cook them with a solid dose of olive oil and they're both healthy and filling. Or use coconut oil, which has more saturated fat (making it taste a bit better but be potentially a bit less healthy).
A few years ago my wife wanted to try the "plant-based" diet. I told her I don't care what I eat as long as it tastes OK, fills me up, and has enough protein. We did it for a month, and I never had any problems feeling full, and I definitely didn't load up on pasta. In the end she decided full plant-based wasn't for her, but we still end up cooking some of the plant-based recipes we picked up from that time few times a week.
It's the recipe / workflow thing that's really the issue. You can't just eat what you were eating before but without meat, and making imitation meat things is generally a recipe for disappointment. Making a good-tasting meal with beans or grains takes a shift in mindset and a shift in equipment if you're used to making food with meat. But once you get it figured out, it's fine.
I thought vegetarians were famous for eating lots of beans and tofu. Is this no longer part of the stereotype?
Refined sugar and carbs are high in calories and low in nutrients. If you eat 2000 (or appropriate for you expenditure) calories of brocoli, you ain't getting overweight.
Additionally, most people are addicted to sugar and refined carbs. Half the problem with diets is getting over that. It is likely the problem defined as satiety--but really just cravings.
We are just starting to get more Randomized Controlled Clinical Trials on diets and such. Will never be perfect, but there is just not enough highly controlled research as it is very hard to implement. But I think with keto, carnivore, vegan, paleo, all fighting to claim to be most healthiest diet, there are folks starting to put money into researching them on equal footing. So we will see.
I think to summarize Michael Pollan, eat whole food, not too much and mostly plants is probably a good bet on healthy diet.
This article [1] is a good writeup of the study (with the original study linked) and does a very good job at contextualizing the results and limitations, alternative viewpoints, and criticisms. My takeaway is, while a very interesting pilot study, the small sample size, lack of a control group, lack of an alternative group that ate the two diets in opposite order, possible confounding factors including exercise while outside the metabolic chamber, etc. don’t make this study any kind of smoking gun.
[1] https://www.medpagetoday.com/primarycare/dietnutrition/59012
Some people can’t wait for the data to come in, they’re suffering now, especially when special interest groups that want people to be vegetarian muddy the waters with agenda studies. All I can trust is how I feel personally eating different ways, and eating whole cuts of meat is keeping me from vomiting up my stomach acid in the middle of the night as my “completely normal stomach” (according to my doctor) tries to digest my trachea.
Legumes in particular are extremely filling: https://www.azumio.com/blog/nutrition/beans-skinny-food
There was a time when animal products were a lot more expensive and scarce. When you add more foods with water in them (provided you're not overloading those foods with fat and oils) you end up feeling more satiated.
Big salads? Fiber tends to make you feel full.
To fix that, most successful diets rely on increasing the ratio of protein you eat (wether it's fish, meat or poultry). It gets you to the same satiety but eating less carbs, and you lose weight.
Now enter plant based / animal free diets, how are people gonna get to satiety without all that dense meat / fish / chicken?
If you're some amazing diet expert, I have no doubt you can figure out a way to get to satiety without relying on carbs. But most people, what are they gonna do? Just get two more slices of bread, or 50% more pasta.
If you strictly oppose a meat only diet VS a plant only diet, people will be leaner on the first one.