Eating highly processed foods could be associated with weight gain finds a new study. The study was published in the last issue of Cellular metabolism and is titled, "Ultra-processed diets cause excess calorie intake and weight gain: a randomized controlled trial of hospitalized patients Ad libitum Food intake. "
In the United States, currently around 40 percent of adults are obese, according to 2015-2016 data from the Centers for Disease Control and Prevention (CDC). Weight gain not only leads to problems like heart disease, diabetes, stroke and kidney disease, but also tumors. Numerous studies have shown an increase in the epidemic of obesity in parallel with the promotion and the meteoric increase of processed and ultra-processed foods. In fact, ultra-processed foods make up 58 percent of the energy consumed.
Selection of frozen food, processed, ready. Credit Image: Yolanta / Shutterstock
Researchers have defined ultra-processed foods as canned ready meals or packaged snacks, etc. They write that these foods often contain high amounts of additives such as colors and aromas and are also rich in trans fats, salts, carbohydrates and processed sugars. These additives and artificial colors are often added to increase the palatability of these foods. The authors explain that sometimes different flavors and ingredients like corn, wheat and soy are mixed in various proportions to make them more profitable. On the other hand, whole foods are consumed as they are originally present in nature with minimal modifications.
The team writes that previous studies have revealed that people who eat more ultra-processed foods are at greater risk of cancer and obesity. This could be due to the ingredients of these foods. To explore this, a team led by physiologist Kevin Hall of the National Institute of Diabetes and Digestive and Kidney Diseases and colleagues conducted an experiment involving 10 men and 10 women who lived on-site at the National Institute campus. of Health in Bethesda, Md. For four weeks. Participants were provided with a diet of whole foods for two weeks or a diet including ultra-processed foods for two weeks. For the next two weeks the diets were alternated. Both types of meals offered the same number of calories, sugar, fat, fiber and other nutrients for the participants. Participants were given the opportunity to eat as much as they wanted in an hour. For each of the participants, snacks were provided all day. These were appropriate for the type of diet the participant was in. Together with these meals they were provided twice a day.
The dott. Hall said in a statement: "I was skeptical that we would see differences in the number of calories people ate, which was the main interest of our study." He went on to say that they observed differences in the outcome of both types of diets. They decided that when they were allowed to eat as much as possible, people on an overprocessed diet had an average of 500 calories more per day than they did when they were on whole foods. As a result when they were on the processed food diet, they gained about two pounds or an average of one kilogram in the two weeks of processed diets. Hall explained that this leads us to the question of what causes people to overeat and it was not just the sugar or fat in these diets that caused the weight gain. They explain that those on ultra-processed diets eat faster and consume more. This speed, they hypothesize, alters the molecular signals generated in the body that tell a person to stop eating. "When people consumed the unprocessed diet, the levels of a hormone called PYY, which is an appetite-suppressing hormone secreted by the intestine, actually increased. And in the same way, another hormone that is known to induce hunger, called ghrelin, died on the unprocessed diet, "said Hall.
The authors of the paper also wrote that the weekly cost of ingredients to prepare 2000 kcal / day of ultra-processed meals was about $ 106 compared to $ 151 for full meals. They calculated the prices of the ingredients sold at a local branch of a large supermarket chain.
The study authors wrote that nine participants were up to 1,500 kilocalories a day more when they were on an ultra-processed diet than when they were on whole diets. In total 11 people gained more weight while on ultra-processed foods than when they were on whole foods. This weight gain was six kilograms in two weeks they wrote. However, some of the participants did not show weight gain even when they wrote ultra-processed diets. Hall said, "We don't know what drove these differences," adding that these changes were independent of age and sex. He also said that there could be differences if diabetics and people with heart disease were included in the study.
The dott. David Ludwig, a pediatric endocrinologist at Boston Children 's Hospital was not associated with this study. He said that this study was in an artificial environment that can affect eating behavior in many ways: "It's social isolation, stress, boredom and the fact that foods are prepared in a laboratory," he explained. While these types of studies "are interesting and useful, they are not the whole story," he said. He said: "There are potentially thousands of different nutrients and factors in food that could affect our biology or our senses while we eat. Those can interact in unpredictable and complicated ways."
Barry Popkin, a professor of nutrition at the University of North Carolina, is another expert who has studied the effects of processed foods on weight gain. Furthermore, it was not associated with this study. Popkin said in a statement: "The difference in weight gain for one (group) and weight loss for the other during these two periods is phenomenal. We have not seen anything like this." He concluded, "We should try to eat as much food as possible. That can be vegetable food. It can be pet food. It can be (unprocessed) beef, pork, chicken, fish or vegetables and fruit. And you have to be very careful when you start going in. other types of food ".
Dariush Mozaffarian, dean of the Friedman School of Nutrition Science and Policy at Tufts University, praised the team for combining the two types of diet in terms of calories, sugar, salt, protein, carbohydrates and fiber. Mozaffarian in a statemtn said: "These are key findings that food processing makes a big difference in how much a person eats." He added that "Putting people in a controlled environment and giving them food allows you to truly understand biologically what is going on, and the differences are striking."
Elisabetta Politi of the Duke Diet and Fitness Center in Durham, North Carolina, said in her statement: "Satiety is higher and lasts longer when we eat foods that have been minimally processed".
The dott. Gunter Kuhnle, from the University of Reading, said that most ultra-processed foods are so processed to increase "palatability, safety and conservation". He said, "This is a well-designed and well-conducted study with interesting, though perhaps not surprising, results. It seems that the participants found the ultra-processed food more palatable, ate faster and consequently more, perhaps because it took more time to feel full. "He concluded," A very interesting result of the study is the cost per energy: the ultra-processed diet was considerably cheaper than the unprocessed control diet, and this probably has health implications. public ".
Dr. Rekha Kumar, an endocrinologist and assistant professor of medicine at NewYork-Presbyterian and Weill Cornell Medicine in New York, called this "big study": "Although the obesity epidemic was related to the growing prevalence of processed foods consumption, this is the first time we see this in a controlled and randomized study.This type of study is difficult to do.I have the feeling that other things, like blood glucose and liver enzymes, would go wrong with these ultra foods too -processed in a long-term study ".
Is the high consumption of ultra-processed foods associated with an increased overall risk of mortality?
A couple of months ago, in February of this year, a group of researchers led by Laure Schnabel published a study showing how eating ultra-processed foods could shorten the life span. The team published their results in JAMA Internal Medicine. The study was titled "Association between ultra-process food consumption and mortality risk among middle-aged adults in France".
The study included 44,551 French adults aged 45 or over. Their diet was evaluated for a period of two years and about 15% of their diet came from ultra-processed foods. Following participants up to the age of nine, they noticed that high intake of ultra-processed foods posed a greater risk of premature death due to all causes. The most important causes of death were heart disease and cancer among these patients, they noted. The authors explain that the risks of these diseases could be due to the excess of salt and sugar and fat in these diets.
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