There’s this popular study that investigated how an ultra-processed diet affects body weight (spoiler alert: ultra processed food just might be making us fat). Researchers invited twenty people, split into two groups, to live in a research environment for 28 days where the three main meals and snacks were provided. For the first 14 days, one group was assigned to an unprocessed diet, while the other group was assigned to an ultra-processed diet. Then, for the second 14 days, the groups switched diets. Importantly, the researchers presented the meals to the participants on plates of similar amounts of calories and told the participants to eat as much or as little as they would like. When following the ultra-processed diet, participants gained 2 pounds, while on the unprocessed diet, they lost 2 pounds. Gaining on an ultra-processed diet isn’t all that surprising, but what really interested me is when participants were most affected by the ultra-processed diet: breakfast and lunch. Participants ate 500 more calories per day on the ultra-processed diet, but dinner is not when they ate these extra calories—it was during breakfast and lunch.
On both of the diets, participants ate about the same amount of calories at dinner and from snacks. But, when following the ultra-processed food plan, participants ate 124 more calories at breakfast, and 213 more calories at lunch than they did on the unprocessed diet. All in all, the researchers summarize that you might expect to be consuming an extra 500 calories from those first two daily meals, give or take, when following an ultra-processed diet. This study lasted only a month, imagine how a lifestyle of eating ultra processed food might make you fat.
Scientists have developed the NOVA Classification System to help us define food according to their level of processing. According to NOVA, the four different groups are: (1) unprocessed foods such as wheat or eggs (2) processed culinary ingredients such as butter or sugar (3) processed foods that are made up of NOVA 1 foods combined with NOVA 2 foods such as fresh baked bread or salted nuts and (4) ultra-processed foods that are made of ingredients not typically found in home kitchens, such as breakfast cereals and packaged frozen pizza rolls.
Eating Simple Meals is the way to go
From the results of the study, it’s no wonder why nutritionists generally advise people to follow the five-ingredient rule: don’t eat prepared foods that have more than five ingredients. The caveat is that if there are more than five ingredients in the dish you’re about to eat, make sure that they’re spices or simple foods that you can have in your own kitchen. (For example, a lunchtime favorite of mine is the packaged meals from Maya Kaimal Organic’s that are made of lentils, butternut squash, coconut cream, and a ton of spices that could have easily been made at home).
The study participants ate about the same amount of calories at dinner and snack time regardless of whether they were following the unprocessed or ultra-processed diet. But, they ate 500 more calories during breakfast and lunch on the ultra-processed diet than they did on the unprocessed diet. Given these results, one strategy to eat fewer calories is to front-load your day with NOVA 1, 2, and 3 foods, and to save any group 4 meals and snacks for after lunch. Because minimally processed meals are higher in fiber, which is known to keep us satiated, you may be so full from breakfast and lunch that you won’t even crave the hyper-palatable ultra-processed meal at dinner.
Put down the PopTarts and have a bowl of oatmeal for breakfast. Toss the Taco Bell and make a homemade steak and veggie rice bowl with corn tortillas for lunch. Only after that, if you really feel for it, should you have the Hot BBQ chips and Skittles for snack, and the frozen mozzarella sticks and fries for dinner.
Simple daily meals to avoid allowing ultra processed food to make you fat
At around 8:30am, I tend to take a heavy breakfast of eggs with toast, butter and jam, fruit, maybe breakfast sausages, and black coffee. This keeps me full until lunch at about 2pm where I’ll probably have rice or pasta with something meaty like a stew or baked chicken and veggies, plus fruit and homemade butter cookies for dessert. Some days, at 4pm, I snack on plain Lays potato chips and some chewy candy, if I’m craving it. Then, I’ll fast from 4:30pm until the next day at at least 8:30am, where I’ll start the day right with a homemade breakfast. This just works for me the way my current work schedule is set up, but try your own variation.
Of course, the best option would be to go for unprocessed meals and snacks all day. Ultra-processed foods are, to a certain extent, “pre-digested”—they’re often stripped of fiber so there’s no real “bulk”, and they may be soft and easy to chew. That might be why, in the study, the meal eating rate was much higher during the ultra-processed diet. As a fast eater myself, I tell myself to slow down and savor every bite because I’ve learned that people who eat quickly tend to have higher BMIs than people who eat slowly. The increased calorie intake found in the study was surely influenced by the faster eating rate, which explains the weight gain.