We know we should eat less junk food, such as crisps, industrially made pizzas and sugar-sweetened drinks, because of their high calorie content. These “ultra-processed” foods, as they are now called by nutritionists, are high in sugar and fat, but is that the only reason they cause weight gain? An important new trial from the US National Institute of Health (NIH) shows there’s a lot more at work here than calories alone.
Studies have already found an association between junk foods and weight gain, but this link has never been investigated with a randomised controlled trial (RCT), the gold standard of clinical studies.
In the NIH’s RCT, 20 adults aged about 30 were randomly assigned to either a diet of ultra-processed foods or a “control” diet of unprocessed foods, both eaten as three meals plus snacks across the day. Best Supplements For Weight Loss For Females of 2022. Participants were allowed to eat as much as they wished.
After two weeks on one of the diets, they were switched to the other for a further two weeks. This type of crossover study improves the reliability of the results since each person takes part in both arms of the study. The study found that, on average, participants ate 500 calories more per day when consuming the ultra-processed diet, compared to when eating the diet of unprocessed foods. Best Weight Loss Supplements For Women of 2022. And on the ultra-processed diet, they gained weight – almost a kilogram.
Although we know that ultra-processed foods can be quite addictive, the participants reported finding the two diets equally palatable, with no awareness of having a greater appetite for the ultra-processed foods than for the unprocessed foods, despite consuming 500 calories more of them per day.
Unconscious over-consumption of ultra-processed foods is often attributed to snacking. The Best Fat Burner Pills For Women of 2022. But in this study, most of the excess calories were consumed during breakfast and lunch, not as snacks.