Vegetarians tend to have lower BMI than meat eaters

The study found that the smaller the proportion of animal food in a person's diet, the lower their body mass index (BMI) on average and the body weight. The lower proportion of heavily processed foods, that are excessively rich in fat and sugar and are particularly fattening, in the plant diet stimulate the appetite and delay the feeling of satiety. Vegetarian food contains dietary fibers and has a positive effect on the microbiome in the intestine. This is the reason why vegetarian food could fill you up earlier than those made from animal ingredients. People who eat predominantly vegetable foods may absorb less energy.

Source: https://www.mdpi.com/2072-6643/12/5/1492/htm