10/09/2026
508 calories a day. Eaten without intentionally choosing to, without noticing, and without feeling any fuller.
Kevin Hall and his team at the National Institutes of Health published this study in Cell Metabolism in 2019, and I think it is one of the most important nutrition studies of the last decade.
They admitted twenty adults to a research ward where every single thing they ate could be measured. They did two weeks on an ultra-processed diet, two weeks on an unprocessed diet, in random order.
And this is the clever part. The two diets were matched for presented calories, for energy density, for protein, carbohydrate and fat, for sugar, for sodium and for fibre. On paper they were the same. People could eat as much or as little as they liked.
On the ultra-processed diet, they ate an extra 508 calories a day. They gained just under a kilogram in two weeks. On the unprocessed diet, they lost just under a kilogram.
Here is why I am bringing it into an episode about meal planning. That gap is not a knowledge problem. Nobody in that study was confused about which food was which. The gap opens because of what is available and what is easy at the moment of eating.
And the single biggest determinant of what is available and easy in your house on Wednesday night is what you decided on Sunday.
I go through the whole system in episode 14 of my podcast, Nourish, Heal & Rise. Listen or watch on Apple, YouTube or Spotify, or visit www.andrearobertson.health/podcast/14
Andrea x
Dr Andrea Robertson
Osteopath | Naturopath | Nutritionist