I'll google rice and lentils as an alternative to eating beef, chicken and other meats for daily protein. If that works I could really go for it. I tried not eating meat years ago without any reliable vegetable proteins. I got so lethargic it felt like I was getting sick so I went back to eating meat. I mean since the protein and vegetable subject is being discussed I though I'd mention it.
I've been a vegan 2 and 1/2 years now, and did a lot of reading on the subject. I haven't lost any muscle mass (not that I was a bodybuilder or did a lot of weight lifting, but I did/do have a normal amount of muscle), but I did drop 20 lbs without any other effort. It's not just rice and lentils, there are a lot of complementary foods that will do the same thing, and there are a few complete protein foods (soy, quinoa, seitan, and buckwheat are, to name a few) from non-animal sources that are equally good protein sources, if not quite as high in "protein quality" as, say, egg. I like soy in tofu or tempeh form, and buckwheat in Japanese noodles like udon and soba.
The idea of "complete" proteins is often misunderstood or misapplied, too. A complete protein food has amino acids in a 1:1:1... ratio, but that doesn't mean your body can't build muscle from even just a single source of incomplete protein, it's just slightly less efficient at doing so, meaning you need to eat a little to a lot more, depending on the amino acid(s) it is deficient in. Some people seem to think an incomplete protein food won't enable you to build muscle at all, which is simply not the case.
The lethargy comes from being your body being accustomed to eat meat, especially if you eat a lot of processed foods. Any large dietary change, even a positive one, takes about a month to get used to and your energy level will actually be higher after that (if I went in the opposite direction and started eating meat, I'm sure I'd feel lethargic for a while, and my energy level would probably be lower than it is now even after that). You just have to stick with it.
I'm not opposed to people eating meat, and I'm a vegan primarily for health reasons (read
The China Study or watch any of the documentaries on Netflix like
Vegucated) and for self-discipline, but I'm also partly a vegan for ethical reasons because factory farmed animals isn't just about the animals, it also takes about the toll it takes on the workers who process food, and on the environment.
The level of meat, fish, and dairy consumption is excessive in modern Western society (and now increasingly globally) is unsustainable - just look at the well-documented issues regarding water consumption and methane gas production of livestock, or how overfishing is devastating fish stocks - but it's really up to individuals to educate themselves and make the decision for themselves as consumers. The level of meat and dairy we consume in the United States isn't just a natural level of what people eat, it's in large part due to marketing, lobbying, and designing food to be addictive (this
Cracked podcast episode explains it better than I can, and it's not conspiracy type stuff, it's all public record/knowledge that this is going on).
If anyone is interested in becoming a vegan - or in just maybe eating more fruits and vegetables and less meat - I highly recommend checking out #whatveganseat on Instagram. So many people thing being vegan means heavily restricting yourself by eating a lot of salad or otherwise by cheating on the diet, but that's not the case. It's worth checking out if you love food.