Can you lose weight and eat ultra-processed foods? – Deseret News

Even the ultra-processed foods that are touted as healthy could foil an attempt to diet, according to new research that finds weight loss is greater when ultra-processed foods are avoided.

Researchers at University College London found that the level of processing made a difference even in nutritionally matched diets. Those who ate minimally processed foods lost twice as much weight as those consuming ultra-processed food.

The study is published in Nature Medicine.

What are ultra-processed foods?

According to Harvard Health, unprocessed or minimally processed foods are “whole foods in which the vitamins and nutrients are still intact.”

The food is pretty much in its natural form, though it might have been pasteurized or cooked. Examples are carrots, apples, raw meat, melon and raw, unsalted nuts. Processed foods typically have added salt, oil, sugar or other substances.

But ultra-processed foods have had a lot going on.

“They most likely have many added ingredients such as sugar, salt, fat and artificial colors or preservatives. Ultra-processed foods are made mostly from substances extracted from foods, such as fats, starches, added sugars and hydrogenated fats. They may also contain additives like artificial colors and flavors or stabilizers. Examples of these foods are frozen meals, soft drinks, hot dogs and cold cuts, fast food, packaged cookies, cakes, and salty snacks,” per Harvard Health.

Matched diets, different results

For the study, 55 adults were randomized into two groups — one assigned an eight-week diet of minimally processed foods such as overnight oats or homemade spaghetti bolognese. Per a news release from the university, “after a four-week ‘washout’ period in which participants went back to their normal diets, they switched to a diet of ultra-processed food, such as breakfast oat bars or lasagna ready meal.”

The other group followed the diets in the opposite order.

The two diets were nutritionally matched and followed the Eatwell Guide, which is the UK’s government advice on a healthy, balanced diet — including how much fat, saturated fat, protein, carbohydrates, salt and fiber each included, as well as recommended amounts of vegetables and fruits.

“Participants had plenty of food — more calories than they needed — delivered to their home and were told to eat as much or as little as they wanted, as they would normally. They were not told to limit their intake,” the researchers reported.

They all lost weight, a fact that researchers attributed to the “improved nutritional profile” of their meals, compared to their normal diet. But those eating the minimally processed food lost more weight.

“The findings suggest that when observing recommended dietary guidelines, choosing minimally processed food may be more effective for losing weight,” per the study.

“Previous research has linked ultra-processed foods with poor health outcomes. But not all ultra-processed foods are inherently unhealthy based on their nutritional profile. The main aim of this trial was to fill crucial gaps in our knowledge about the role of food processing in the context of existing dietary guidance, and how it affects health outcomes such as weight, blood pressure and body composition, as well as experiential factors like food cravings,” said Dr. Samuel Dicken, first author of the study, from the Centre for Obesity Research at the university.

“The primary outcome of the trial was to assess percentage changes in weight and on both diets we saw a significant reduction, but the effect was nearly double on the minimally processed diet. Though a 2% reduction may not seem very big, that is only over eight weeks and without people trying to actively reduce their intake. If we scaled these results up over the course of a year, we’d expect to see a 13% weight reduction in men and a 9% reduction in women on the minimally processed diet, but only a 4% weight reduction in men and 5% in women after the ultra-processed diet. Over time this would start to become a big difference,” he said.

The study found that participants consumed fewer calories and less fat when eating minimally processed foods.

Should ultra-processed foods be avoided?

As The New York Times reported, “Federal officials have been sounding the alarm about ultra-processed foods, which account for about 70% of the food supply in the United States. Robert F. Kennedy Jr., the health secretary, said that ultra-processed foods were ‘poisoning’ Americans, and called them a primary culprit of high rates of obesity and chronic diseases.”

As the article noted, ultra-processed foods are “ubiquitous and tend to be cheaper than minimally processed foods.” The Times reported that ultra-processed foods don’t need to be avoided completely. But home cooking with fresh ingredients is better.

A number of studies have linked ultra-processed foods to obesity and other health concerns.

In March 2024, Deseret News reported on a study in BMJ linking ultra-processed foods to dozens of health problems, including obesity, heart disease, certain cancers, diabetes and even premature death.

The study found that there’s great variation in how much ultra-processed food is consumed from one country to the next.

Another study Deseret News reported on concluded that ultra-processed foods with lots of refined carbohydrates and added fats can be as addictive as cigarettes. The study, by researchers at the University of Michigan and published in a special food-focused issue of BMJ, said the findings include sweets and salty snacks, among other foods. It noted that, like other addictive substances, ultra-processed food can:

• Create compulsive use.
• Alter moods.
• Reinforce behaviors.
• Spark “intense urges and cravings.”

When Deseret News recently explored healthy aging, interviewing experts and poring through studies, ultra-processed foods made the list of things to avoid as much as possible.