General food questions and everyday fundamentals.
“Healthy fats” usually means prioritizing monounsaturated and polyunsaturated fats over saturated and trans fats. Olive oil, nuts, seeds, avocado and fatty fish are common sources, but all fats still provide about 9 calories per gram.
Saturated, monounsaturated and polyunsaturated fats are families of fatty acids with different chemical structures. In practical nutrition, the main distinction is that monounsaturated and polyunsaturated fats are generally favored, while saturated fat is limited and preferably replaced with unsaturated fat.
The leftover question does not really start on day three. It starts when dinner ends: prompt cooling and a cold refrigerator are what make USDA's 3–4 day window meaningful.
The freezer is not the real question; the thawing history is. USDA generally allows refrigerator-thawed food to be refrozen raw if it stayed cold, while microwave- or cold-water-thawed food should be cooked first.
The ranking changes when the question shifts from 'how much protein is in 100 grams?' to 'how much protein do I get for 100 calories?' Lean fish, egg whites, turkey and chicken suddenly move toward the top.
Chia and flax lead on fiber per 100 grams, while a full serving of beans or lentils can contribute more total fiber than a spoonful of seeds.
Animal proteins generally have high digestibility and favorable essential-amino-acid profiles. Plant foods can fully meet protein needs with adequate variety and also provide fiber that meat, fish, eggs and dairy lack.
Tempeh, tofu, seitan, soybeans and legumes are easy to use as the protein center of a plant-based meal. Nuts and seeds add protein, but their usual servings are smaller.
Aged cheeses, seeds and lean cooked meats rank among the most protein-dense foods per 100 grams, but serving size and water content can change which foods contribute the most protein to an actual meal.