Good Food, Bad Food, I'm the guy with the vectors

The problem with saying food is good or bad is that beyond the psychological connotations it puts on food (that I find just aren't helpful in having a healthy relationship, YMMV), is that it views the complex world of nutrition and homeostasis as an oversimplified scalar.

What is a scalar? In physics class you probably heard about them, and maybe you forgot. Scalars are things with simple +/-, more/less measurements, like temperature.
People talking about good food and bad food are tending to think that food operates like a scalar and that more good food negates more bad food, and that more good food is always a good thing.


Unfortunately, the human body and human nutrition aren't such simple things. We exist in a dynamic equilibrium called homeostasis. Going too much in any one direction means we die. Going too much in the opposite direction and... we die. Nutrition is balancing all of the very different directions we could be headed in to stay near the center. This makes food and its nutrients more of a vector - there's an amount and a direction, similar to velocity - you have a speed (scalar / magnitude) and direction (northwest).
This is why many people say no healthy foods, just diets, or they say that they can't say if a food is healthy without the context of the overall diet.


At a given moment a person's calcium could be low. That means broccoli with its calcium would be a good food. Alternatively, a person have eaten several blocks of cheese today, and be on the way to forming a kidney stone with the excess calcium - now, potentially, the calcium in broccoli is very painfully unhealthy.

So as you can see, anyone saying they can tell you they know a food is good or bad is saying they can know how to get somewhere without knowing where they are. It doesn't make sense.