I would say this is not categorically true. If the subject interests you, OP, you should do your own research. Whether vegetables are healthier before or after cooking is a complicated subject, as there are a lot of vegetables, nutrients, and cooking methods to consider. Available vitamin C is more plentiful in several types of vegetables before cooking, for example, but available lycopene is more plentiful in several types of vegetables after cooking. I frankly don't worry about not getting enough vitamin C.

I also can't agree with or really even understand the comment about frozen veg quality varying by brand. In my experience, frozen vegetables are among the most reliably consistent things you can buy in US grocery stores, whether they're national brands such as BirdsEye and Green Giant or generic store brands.

Overall, I am with uk1 on this; frozen vegetables are often fresher and more nutritious than fresh vegetables. I keep several types of frozen vegetables on hand all the time, use them several times a week, and cook them minimally (a few minutes boiling or steaming).

I concur also on keeping frozen fish in the freezer: unadorned fillets, beer-battered pieces, whatever you like.

Chicken doesn't stock very well in the freezer; its liquid bleeds out and doesn't go back into the meat. (You can tell a frozen/defrosted package of chicken pieces in the grocery store from a not-previously-frozen package; the frozen/defrosted one will have pink-tinged water pooling in the corners of the package. In contrast to chicken, beef and pork both freeze well.

I agree also on making and freezing batches of things like ragu bolognese and curry sauce. Many types of sauces and soups freeze well, but potatoes, rice, and pasta aren't as good when defrosted--frozen/defrosted potatoes are mealy; rice and pastas soak up too much liquid and get blown out. Save containers of sauce or soup without these and add potatoes or pasta fresh. The Italian soup paste e fagiole is a good example: the liquid, tomatoes, and beans will all be fine when defrosted, but you're better off not freezing it with pasta (such as ditalini) in it before freezing, but rather adding freshly cooked pasta to smaller servings that you defrost. Chicken, especially chicken breast, can also get tough if frozen in dishes and defrosted. I occasionally make a big pot of a "chicken a la king" sauce (creamy chicken sauce with sherry and vegetables) that I freeze in containers and later add to freshly cooked chicken meat and biscuits.

Same is true for shrimp or other seafood in soups, sauces, gumbos, etc. The shrimp will be tough after freezing and reheating. Just freeze the sauce and add fresh shrimp later.

I grew up in a household of nine and still find it hard to cook for just two, much less one. Another thing I do, which has already been suggested, is make multiple batches to freeze---meatloaf, for example, as someone mentioned. When I make turkey tetrazzini, I make a lot, serve one dish of it, freeze one or two others. I would do much more crockpot cooking (household of nine, remember) and freezing if Mister Mister weren't so dismissive of crockpot-type meals... I do manage to sneak them in on him occasionally, though. If I lived alone, I would probably make something in the crockpot at least once a week -- but then, I think I'd also buy a smaller crockpot than the one I have.

Bread also freezes well, especially if you suck the air out of the bag. I keep croissants and French bread and the like in the freezer. Forget them too long and they'll get freezer-burned, but use them in a timely fashion and they'll defrost quickly and taste as good as new. Freezing bread preserves it longer than refrigerating it does.

When you come home for lunch or are tired after work, you usually don't feel like defrosting something frozen. Two suggestions for this: (1) occasionally take something out of the freezer a day or two in advance of when you think you'll want to eat it, and let it defrost in the fridge. That gives you a chance to check its texture etc. after defrosting and change plans if necessary. (2) keep some pantry things (canned beans, rice, pasta, canned tunna, canned clams, canned salmon, canned diced tomatoes, garlic, onions, potatoes, also jarred sauces for pasta such as tomato, cream, or pesto-based sauces) on hand for quick meals such as linguine with clam sauce, red beans and rice, tuna salad on a croissant, bruschetta, etc. If you like egg salad, hard-boil a few eggs once in a while.

A thing I've been doing lately once a month or so is buying a bag of frozen meatballs, heating/browning them in the oven, and then crumbling them into some defrosted pasta sauce of my own or even, in a pinch, some homemade spaghetti sauce. The cooked meatballs broken up and some olive oil and seasonings, some sauteed onions and garlic, and a can of diced tomatoes mixed in with homemade or storebought sauce makes for a large quantity of meaty, chunky, tasty sauce that freezes well.