Good Food, Bad Food. Goal Food, Soul Food.

Somewhere along the way it became standard advice that there are no good or bad foods. You've heard it. Probably from a dietitian, almost certainly from an Instagram carousel.

Objectively speaking, there are good foods and bad foods. There are foods that do a lot of work for you and foods that do very little, and the gap between them is not a matter of opinion. It’s ingredients. Nutrients. Processing. Effect on appetite. Personal differences. Etc. What there aren't, however, are good people and bad people who eat them.

A piece of salmon and a bag of chips are not the same, even if they have the same calories. One brings protein, long-chain omega-3s, selenium and B12, and leaves you satisfied for hours. The other brings salt, fat and refined starch in a combination that hits at exactly the right level to keep you wanting to continue to eat them until they are gone, and then feel remorseful that they are gone.

Where the "no good or bad foods" message goes wrong is that we have collapsed food quality into personal character. We do this reflexively. When researchers gave people identical profiles that differed only in what the person ate, participants judged the eaters of "healthy" food as more moral. Qualitative work with adults aged 50 to 70 found people describing their entire relationship with food in terms of saints, sinners and moral boundaries.

So we did the obvious thing. To stop people feeling like sinners, we declared all food morally identical.

The better move is to keep the nutritional distinction, drop the moral one and not make the food we eat a character assessment tool. Chips are lower-quality food. Eating them makes you a person who ate chips. That's it.

There are also foods that buffer your appetite and foods that trigger it. These are different for everybody; you may easily pass up salt and vinegar chips, but I might have one and not be able to stop. There are, though, distinct properties in the food. In a controlled inpatient trial, 20 adults ate an ultra-processed diet and a minimally processed diet for two weeks each. The meals were matched for calories presented, energy density, macronutrients, sugar, sodium and fibre. Participants ate as much or as little as they wanted. On the ultra-processed diet they ate 508 kcal more per day and gained weight. On the unprocessed diet they lost it.

A larger and more recent crossover trial makes the point with more nuance. Fifty-five adults followed two 8-week diets, both built to national dietary guidelines, one from minimally processed foods and one from ultra-processed foods. Both produced weight loss. The minimally processed version produced significantly more. While processing isn't everything, it isn't neutral either. Food you have to chew is food you eat less of.

There are qualities of foods which slow down eating rate, keep you fuller for longer, take longer to eat etc. Protein and fibre are two such qualities. This is what is meant by buffer versus trigger. Some foods flatten the curve of your appetite. Some foods sharpen it. Knowing which is which for you is as useful as any calorie target.

One thing also worth discussing is that there are always foods that people eat that are not moving you toward your goal, but make up a big part of why we eat and what we enjoy. Not everything we eat needs to have a ‘health’ or ‘aesthetic’ purpose.

Robin Dunbar's analysis of a UK national survey found that people who eat socially more often report being happier and more satisfied with life, are more trusting, are more engaged with their communities, and have more friends they can rely on. Researchers looking at why the Mediterranean diet performs so well have argued that conviviality is one of its consistently underrated ingredients. Your mum's pavlova at Christmas is not a nutritional decision. Neither is the beer after a long run with people you like, or the meal your kid asks for on their birthday. Removing guilt from this is an important part of your overall eating pattern. And, truthfully, if it were true that feeling bad about food made people eat better, this would all be academic. It isn't true.

In a study that illustrates this, participants were asked whether their default association with chocolate cake was "guilt" or "celebration." The guilt group did not report better attitudes toward healthy eating or stronger intentions. They reported lower perceived control over their eating, and they were less successful at maintaining their weight over the following 18 months. Among those with an active weight loss goal, the guilt group lost less weight over three months. A follow-up found the guilt association was reasonably harmless under low stress, and clearly worse under high stress.

A related finding is that flexible restraint has been associated with better long-term weight loss and maintenance, while rigid restraint has been associated with less weight loss, more disinhibition and more binge eating. So it’s not that structure is the problem. Structure is often the answer. What the evidence consistently does not support is self-punishment as a strategy.

So, where to go with this information? Four questions to ask yourself:

1. Does this move me toward the thing I said I wanted? If yes, it's goal food. Protein, vegetables, fruits, foods that arrive roughly as they grew. Build the majority of your intake here.
2. Does eating this leave me satisfied, or hunting? Track it for a fortnight. Some foods will be fine for you and others will leave you distracted, hungry and wanting more.
3. Is this meal doing a job that isn't nutritional? Connection, celebration, memory, or plain enjoyment. Those are legitimate.
4. Am I choosing this, or is it choosing me? This is the only question that really separates soul food from something else, a trigger food. It’s not that you can never eat it, but understand the hold it might have on you.