The food that is dangerous not only to the heart: A new study published in the journal Radiology points to a link between the consumption of ultra-processed food and the accumulation of fat within the muscles, a process that may impair muscle function and affect overall health. The researchers emphasize that this is an effect that is not dependent only on excess weight or high calorie intake, but is directly related to diet quality.
The study included 615 participants with an average age of about 60, who were included in a large database dealing with osteoarthritis. The researchers examined the participants’ dietary habits alongside MRI scans of the thigh muscles, in order to assess the amount of fat accumulating within and between the muscles.
The findings showed that people who consumed more ultra-processed food, such as salty snacks, sweetened beverages and fast food, exhibited higher levels of fat between the muscle fibers. This is fat known as intermuscular fat, which tends to accumulate in conditions of inactivity or metabolic disorders. The researchers presented in their article one of the MRI images of the thighs of one of the women examined. Her diet included 87% ultra-processed food. The imaging showed many fat deposits between the muscle fibers.
Contrary to what might have been expected, the link between processed food and muscle fat remained significant even after adjustment for factors such as body mass index, calorie intake and level of physical activity. That is, even people of normal weight or those who are physically active may be affected by the composition of their diet.
According to the researchers, fat within the muscle is not just an aesthetic phenomenon, but has broad physiological significance. Fat accumulation changes the structure of the muscle and impairs its ability to generate force. When it comes to the thigh muscles, this impairment may affect knee stability and accelerate degenerative processes in the cartilage, which increases the risk of osteoarthritis.
The comparison proposed by the researchers illustrates the difference: A healthy muscle resembles a lean cut of meat, while a muscle with excess fat resembles a fatty cut in which the fat is integrated within the tissue. The difference is not only in appearance but also in function.
Previous studies have shown that an increase of 1% in intramuscular fat raises the risk of heart disease by about 7%. Additional links have also been found to type 2 diabetes. One hypothesis is that fat in the muscle secretes inflammatory substances, such as cytokines, which contribute to the development of chronic diseases.
Ultra-processed food, beyond its high calorie content, is also characterized by a lack of essential components such as high-quality protein, omega-3 fatty acids and iron. These components are essential for building muscle and maintaining its proper function. When the diet lacks them, the muscle has difficulty maintaining a healthy structure.
The researchers emphasize that it is still not possible to determine a full causal relationship, but the findings point to a clear direction that justifies further research. If it is indeed proven that ultra-processed food causes fat accumulation in muscles, the implication will be a change in the recommended dietary approach, not only for preventing obesity but also for preserving muscle mass.
Despite the worrying findings, the researchers also have an encouraging message: It is possible to reduce fat in the muscle through a change in lifestyle. A diet based on healthy foods, together with regular physical activity, may improve muscle condition over time. However, this is a gradual process, since fat does not accumulate overnight, nor does it disappear quickly. The meaning is simple but substantial: Not only how much you eat, but what you eat, may affect the body and health.