Whether frozen pizza, ready meals or the pre-mixed breakfast porridge: Convenience food is popular, quickly consumable and usually not too expensive. But these highly processed foods have a dark side. Even with the same number of calories and nutrient shares, losing weight with such ready meals is significantly more difficult than with a little processed food, as a British study now operates. The 55 overweight test subjects lost after eight weeks with finished products half as much weight as with freshly prepared dishes, and the fat content of your body also fell less. The participants also reported that with fresh, less processed dishes they had fewer cravings and ravings than with the ready meals. According to the researchers, this confirms that the strong processing of many finished products could also play a role in the worldwide increase in overweight.
Ready dishes and other high -quality food products should make everyday life easier and reduce time and effort to cook. You simply push the dishes into the microwave or the oven and you have a meal. But in order for this to work, the food must be processed in such a way that they remain stable for a long time, microbiologically harmless and taste. As a result, the highly processed products usually contain a lot of sugar, salt and saturated fats, as well as plenty of additives such as emulsifiers, preservatives and sweeteners. However, fiber are often less contained than in freshly prepared, less processed dishes. For a long time there have been increasing the indications that the enjoyment of predominantly highly processed foods in the long run has negative consequences for health. So you are suspected of promoting colon cancer, cardiovascular diseases and obesity.
So far, however, it has so far been controversial what this is and whether the degree of processing of the food really plays the decisive role. Because often people who eat a lot of finished products also live historical overall. This makes it difficult to separate the effect of the highly processed food from the remaining influencing factors. “Only in a precise test series that specifically compares the highly and minimally processed food in a well-controlled experiment and only uses the processing level as a comparison size can the health risk from highly processed products,” explains the not involved in the study Stefan Kabisch from Charité Berlin. But such studies are extremely complex and expensive. “So far, there have been very, very few studies in the entire research history that have met these high quality features,” continued Kabisch.
Only half as much weight loss with finished products
One of these studies is now the study by Samuel Dicken from University College London (UCL) and his colleagues. They have delivered 55 overweight and obese test subjects of middle -aged food for months in order to compare the influence of highly processed compared to little, freshly prepared dishes on weight and health. For the study, the test subjects initially received either the highly processed or little processed food for eight weeks. The dishes and products were selected so that both groups were given food with the same calorie content and the same nutrient shares. The ready meals were also not a maximum of unhealthy, but had the classification up to a maximum of orange on the diet. All test subjects could eat as much as they wanted, and the groceries were not rationed in any form. After eight weeks, a four -week break followed before the groups were exchanged for eight weeks. All participants were medically examined before and after the respective study phases and their weight, body fat percentage and muscle mass were measured. In addition, thick and his team all test subjects responded to how strong their appetite was, how often they had cravings and determined the calorie content of the food consumed.
The evaluations showed that all test subjects had lost easily in weight, but the effect of the group with little processed foods was almost twice as high: in the eight weeks they decreased an average of 2.06 percent, the test group with the highly processed finished products only around 1.05 percent. The body mass index and the body fat percentage also improved significantly more with the less processed food than with the finished products. “Even if a weight reduction of two percent appears low, it must be taken into account that this happened within only eight weeks and that the participants did not deliberately restrict their calorie intake,” emphasizes Dicken. If the weight loss is high for one year, the participating men with little processed food would have decreased around 13 percent, the women nine percent. With the highly processed finished products, it would only have been four or five percent. During the study, however, the test subjects did not know that the study was about losing weight. “This blinding of the actual study goal is an important element, because this is the only way it could happen unconsciously and imperceptibly,” comments Kabisch. “The physical activity should also remain the same and was demonstrably unchanged about the duration of the studies and without difference between the groups.”
More cravings
The study also showed that in the phase with little processed, freshly prepared dishes, the test subjects felt significantly less cravings and appetite for sweets or junk food than with the highly processed finished products and less overall. The causes of this are unclear, but in theory there are several reasons conceivable, as Kabisch explains: “Highly processed foods are optimized for our addictive behavior, in particular strong sweet stimuli prevent saturation. Because slightly digestible carbohydrates lead to stronger blood sugar fluctuations, which in turn lead to a new feeling of hunger shortly after the meal,” said the metabolic doctor. In addition, ready meals are often softer and have to be chewed less. This means that we eat them faster and the feeling of satiety does not come after. According to the researchers and also not involved in the study, this study confirms that it is cheaper for losing weight and weight control to do without finished products and to eat as unprocessed or less processed food.
“Our study shows how important processing for the health effects is – in addition to nutrients such as fat, salt and sugar,” says co -author Chris van Tulleken from University College London. He and his colleagues advocate making this more public – for example through warnings and information. At the same time, they think it makes sense to intervene in terms of regulatory
For example through advertising restrictions, taxes and subsidies. “The best advice is to follow nutritional recommendations as much as possible, to control the total energy intake, to limit the consumption of salt, sugar and saturated fats and to eat as many fiber -rich foods such as fruit, vegetables, legumes and nuts,” says senior author Rachel Batterham from University College London. “Fresh food and self -cooking brings advantages for body weight, body composition and health as a whole.”
Source: Samuel Dicken (University College London) et al., Nature Medicine, DOI: 10.1038/S41591-025-03842-0
