The measure that matters more than calories alone
Calorie density is simply the number of calories in a given weight of food. It sounds unremarkable, but it may be one of the most useful ideas in nutrition, because of one reliable human habit: most of us eat a fairly consistent weight of food each day, almost regardless of what that food is. Eat foods that are naturally lower in calories per pound, and you'll tend to eat fewer calories overall, without consciously trying to.
A forty-times difference
The range is startling. Non-starchy vegetables average around 100 calories per pound. Oils and fats average around 4,000, meaning a single tablespoon of oil already carries roughly 120 calories, before you've eaten anything else. Research suggests that an overall diet averaging around 400 calories per pound tends to produce weight loss even without exercise; at 800 calories per pound, weight loss generally still needs some activity; above around 1,200, most people gain weight unless they're highly active.
Why whole foods sit at the low end
It's not a coincidence that almost every naturally low-density food is a whole plant food. Whole foods carry their water and fibre intact, which bulks them out without adding calories, along with their full complement of nutrients. Refining strips exactly those things away: whole grains average around 500 calories per pound, but refined versions of the same grain can run to 1,400, having lost as much as 80% of their original nutritional value along the way. Pasta is the interesting exception — it absorbs so much water during cooking that its density drops substantially, calories and all.
The upshot
None of this requires counting anything. Favour whole, unrefined, plant-based foods, and calorie density does a great deal of the work on your behalf, which is largely the thinking behind what lands on your plate, and in your glass, during a stay here.
