The thing is, it seems to be a lot easier for people to lose weight if their directions for Good Food and Bad Food are clearly drawn. When you start getting into refined details, or things that require a lot of self-awareness and serious discipline (like eating exactly five potato chips), then most people don't stick with it. Losing weight as a vegetarian is easy for most people (I'm talking clinical trials here, not individual experiences) simply because the "what am I gonna eat" choices are so straightforward. Lots of restaurants, if you're eating vegetarian, you're eating a salad and an appetizer, and that helps with portion control too.
PC: The only meat I eat is venison (from friends and relatives who hunt and dress it themselves) and fish. Which means that most of the time, I'm effectively vegetarian.
Stuff that is easy and vegetarian:
Stir-fry. DH is the king of stir-fry. For stir-fry tofu, marinate sliced firm tofu overnight in a mix of equal parts cider vinegar, maple syrup (real stuff, not the fake kind) & water, mixed with a generous amount of finely chopped fresh ginger and garlic. Take the tofu slices out of the marinade (save the marinade), then dip them in cornstarch and pan-fry them in peanut oil until golden brown. Drain on paper towels. Then, add the leftover marinade to the pan and let it simmer to cook down for 20-30 minutes. Add soy sauce & hot red peppers to taste. Thicken the sauce with a couple tsp. cornstarch you've got left over. Microwave some veggies and put the veggies and tofu over brown rice, pour sauce on top.
Potatoes smothered in steamed broccoli and cheddar. Easiest thing on earth, you just microwave a potato, microwave some broccoli. grate cheese on top--it melts from the heat of the veggies. I usually poach an egg and mash it into the middle of the baked potato, which DH says looks disgusting but tastes wonderful.
Quesadillas: cheddar or jack cheese with baked beans is my fave.
This time of year, I'm using up stuff from the pantry & root cellar, so we're eating a lot of bean soups: Mix 3 tbsp. oil and 2 tbsp. flour in the bottom of a soup pot on med. heat. Gradually add veggie bouillon until the soup gets rather thin. Then add whatever you've got for frozen veggies and rinsed canned beans, mixed herbs to taste. I put in Quorn chicken tenders, which seems to be a love-it-or-hate-it thing for meat substitute, but it does have a reasonable amount of protein and I think it tastes OK. Maybe not like real meat, but OK.
Chowda: Do the oil & flour thing again, but this time use 1 1/2 c. stock and 1 1/2 c. milk to make the soup instead of all stock. Add chopped fried onion & celery, frozen corn, chopped red pepper, cubed potatoes, cheddar cheese, mixed herbs, cook till done. DH is fond of yeast extract (Marmite) in his soups, but I am not a fan.