This one comes with some disclaimers. I am not a doctor or a nutritionist or a dietician. I have a certification in fitness nutrition and opinions, but the scope of my practice does not extend to designing diets (in the sense of what people eat, not in the sense of what people avoid eating to reduce weight). What follows is within the scope of my practice, which is general advice about macronutrients and micronutrients. When I am giving my personal opinion, I will say so.
Nutrition can be complicated because we are each lovely individual snowflakes with our own bundles of food preferences, sensitivities, and metabolic propensities. It is my opinion that we all have to do some experimenting to figure out, within the parameters of science, works best for our bodies. It is also my opinion that there are no inherently “good” or “bad” foods, that no one should punish themselves for eating anything, and that health comes from happiness as well as other things.
However, there are some general guidelines that it is good to keep in mind. Food is made up of what are called macronutrients (carbohydrates, proteins, and fats) with small amounts of micronutrients (our friends the vitamins and minerals). While there are exceptions (looking at you, keto eating plans), most people seem to do best on eating plans that are sparing with fats, moderate with proteins, and heavy on the complex carbohydrates.
All macronutrients are not, however, the same. Fats come in a range from fully saturated to fully unsaturated. The easy way to tell a saturated fat is that it is solid at room temperature. In general, the more unsaturated a fat is, the better it is for us. Fats are tasty (mmm…. butter!) and give us a lot of calories in small doses. They also can help us feel satisfied at the end of a meal. People who want to reduce their calorie intake often find that cutting the fat content helps a lot.
Protein is the macronutrient we use to build our tissues. Virtually no one in our culture needs to worry about protein intake. We all get plenty. Animal proteins often come packaged with a pretty high fat content, so we want to pay attention to that a little. And, for those of us who have not been paying attention for a long time: vegetarians have no problem getting enough protein and vegans just have to be a little conscious of getting a wide range of essential amino acids.
Carbohydrates are the current favorite target of bad press. This is undeserved. Our brains function on glucose, which is a simple carbohydrate. Now, we are not hummingbirds, so just sucking down red syrup is not enough to make our brains and bodies function well. Simple carbohydrates, like glucose and other sugars, join together into larger molecules to form starches. In general, the more complex a carbohydrate is, the better it is for us. Bulky starches and their friend fiber are our friends because they make us feel full and they keep our digestion moving along. Mom was right: we should eat our veggies.
The thing is, we don’t eat macronutrients; we eat foods. Our best bet when choosing foods is to pick the least processed versions. An apple is better than apple juice in terms of nutritional bang for calorie buck. That said, we don’t chow down on a pile of wheat. Choose foods that are less processed when possible.
Micronutrients are generally not a problem if we select a wide variety of foods. I am not a super proponent of lots of supplements, but a multivitamin is a reasonable insurance policy against any gaps in our food plans.
Finally, drink water. Most of us don’t drink enough water and we tend to drink too much other stuff that is full of calories. Water makes us nicer, really.
To sum up: eat veggies and drink water. The rest is pretty optional.