Rainbow Diet

Processed food increases weight and obesity

People eating whole foods eat less calories and lose weight, while people who eat processed food pack on the calories and weight, according to major research in Cell Metabolism (1).

In the first controlled, randomized study to directly compare the differences in people’s calorie consumption and weight gain on an unprocessed food diet versus one that is ultra-processed, the results were clear.

Even when both diets were perfectly matched in terms of fats, sugars, salt, calories, and carbohydrates, people simply ate more food and gained more weight when eating a diet of ultra-processed foods.

All healthy volunteers were healthy and stayed at the National Institutes of Health’s Metabolic Clinical Research Unit for one month. They were given one diet for two weeks and then the other for a further two weeks. They had three meals a day. They could eat as much food as they wanted but taste was not a factor as the participants reported all the food tasted good.

Participants consumed 508 calories more per day on the days they ate processed food compared to the days they were given whole foods.

They gained an average of two pounds on the two weeks they were on the processed diet, whereas they actually lost two pounds on average during the two weeks they were on the whole food, unprocessed diet.

They also gained body fat during the ultra-processed diet and lost it during the whole food period.

Apparently, people consume their food more quickly when eating processed food.

The whole food diet included nuts like walnuts, seeds, berries, apples and olive oil, and was similar to a Rainbow Diet.

Chris Woollams, former Oxford University Biochemist said, “We know that the Rainbow Diet with all its nourishing whole foods causes people to lose weight even though the feel full and consume the required calories. In my view it’s the bad fat content and empty calories of processed food that encourage people to take in more calories. And as we know, processed food is less nutritious and the source of all ills”.

Go to: Mediterranean Diet – voted the healthiest diet in the World

* * * * * *


  1. Cell Metabolism, Hall et al. “Ultra-processed diets cause excess calorie intake and weight gain: An inpatient randomized controlled trial of ad libitum food intake” 

Show More
Back to top button