If you buy meat, separate the meat into small portions as soon as you get home, then freeze each portion separately (except what you plan to use immediately). Don't make the mistake I did and freeze the entire pound of ground beef as one unit. Divide it in half or even into quarters before you freeze it. I would suggest separating steaks and pork chops, too, if you buy several at a time. For me, I rarely (if ever) even buy meat these days. It is much simpler for me to eat vegetarian at home (though I will eat meat if someone makes me dinner or I'm eating out). I've just found that eating vegetarian costs less and often makes small-portion meals more easily. This is completely a personal decision, of course. Meat does freeze, so you would be able to make it work.
I have been able to make a greater variety of foods by making fresh vegetables and fruit a large part of my diet. Many fruits and vegetables, especially fresh, are quite easy to divide into small portions or any size of portions you like. Some, such as eggplant, are more difficult (eggplant doesn't keep once it's cut open). However, most are easy to cook with no matter how many are eating. So, even if you do buy and eat meat, consider adding fresh vegetables.
Below is a list (not all-inclusive) of a few foods that I've found are easy to make in small portion or that make great single-serving meals (or parts of meals):
Sweet Potatoes Spaghetti Broccoli Grapes Spaghetti Squash Oatmeal
Bread (I recommend homemade) Stir-fry Cabbage (small head) homemade pizza
Yogurt Rice/Lentils/Quinoa/Pearl Barley Carrots
TVP (textured vegetable protein) makes a great meat substitute