There’s a new study out providing compelling evidence that a diet high in “ultra-processed” foods is strongly associated with weight gain compared to a diet comprised of whole, fresh foods.
But does that mean we should avoid these ultra-processed foods at all costs?
1. First let’s define ultra-processed foods – what does it mean?
There is no standard definition just yet, but it generally refers to foods that are made with cheap sources of energy and nutrients. They tend to be quick to both prepare and eat – think frozen chicken nuggets, pizza, packaged snacks like chips and crackers, etc.
People in the study followed the ultraprocessed diet for two weeks and the unprocessed diet for two weeks, and the researchers measured their weight and did bloodwork for cholesterol, blood sugar, and and appetite hormones. Participants were able to eat as much of the meal as they wanted.
What happened when they followed the ultraprocessed diet?
When the study participants were on the ultraprocessed diet, they ate about 500 calories more per day and gained about 1 lb/week.
This is really interesting because the diets had the same amount of calories, protein, carbs, fat, and other nutrients. They even had the same amount of fiber, but the fiber was provided in the ultraprocessed diet as a supplement in the beverages. So there seems to be something about the ultraprocessed foods driving people to eat more.
Demo: Smoothie vs yogurt, fruit, milk
They didn’t explore possible mechanisms too much in the paper, but I think a lot of it is related to how long it takes to eat, digest, and absorb food. Similar to how a fruit smoothie might be digested and absorbed very quickly compared to eating a whole piece of fruit and having some yogurt. You’re probably going to be more satisfied and for a longer time from the whole food version.
So should we avoid ultraprocessed foods no matter what?
Not necessarily – I caution people to not get caught up in black and white thinking about these things. Ultraprocessed foods can be delicious and really helpful when you’re short on time.
But the study pretty much confirms what dietitians and the Dietary Guidelines for Americans already recommend (and very few people actually do). Eat plenty of fruits, veggies, whole grains, lean protein, etc. and limit those convenience foods. Balance out a slice of pizza with some broccoli on the side. Have a small piece of cake with plenty of fresh berries to fill you up.