Not all fat that builds up in the liver is the same — it depends on what you eat

"Detox" is one of the first things people reach for when they feel their diet has gone off track. Cold-pressed juices and supplements are popular choices, but there is no solid scientific evidence to back them up. Medical experts advise that instead of relying on specific foods or supplements, people should focus on balanced nutrition that keeps metabolic function running smoothly.

Managing body fat is particularly important — and that means looking beyond the sheer amount of fat in the body to how fat cells themselves are functioning. Fat cells not only store energy but also secrete hormones that regulate appetite and metabolism. Leptin, one of the key hormones produced by fat cells, acts on the brain to control food intake and energy balance. Adiponectin, another fat-cell hormone, plays a role in insulin sensitivity and the metabolism of glucose and fat.

When fat cells malfunction and release excessive fatty acids into the bloodstream, fat can accumulate in the liver and muscles and interfere with insulin action. Whether a person consumes saturated or unsaturated fat can influence how much fat builds up in the liver and around the visceral organs.

"Managing healthy metabolism requires looking at the type of fat you eat, how much you eat, and the overall balance of your diet," said Park Yun-chan, director of Busan 365mc Hospital. "Replacing high-saturated-fat foods like butter with unsaturated-fat sources such as avocado and olive oil is a good place to start."

A study by researchers at Uppsala University in Sweden, published in the journal Diabetes in 2014, supports this view. When 39 adults were given muffins high in saturated fat or muffins high in unsaturated fat over seven weeks, weight gain was similar in both groups — but liver fat and visceral fat increased significantly more in those who ate the saturated-fat muffins.

Olive oil is rich in oleic acid, an omega-9 fatty acid, while avocados provide both oleic acid and dietary fiber. Experts recommend spreading thin slices of avocado on whole-grain bread instead of butter, or drizzling a small amount of olive oil over vegetables. Nuts such as almonds are also a good source of unsaturated fat.

A diet heavy in ultra-processed foods, on the other hand, can have a negative effect on the body's fat management. A study by researchers at the US National Institutes of Health, published in Cell Metabolism in 2019, found that participants who followed an ultra-processed diet for two weeks gained 0.4 kilograms of body fat, while those on a minimally processed diet for the same period lost 0.3 kilograms.

"When managing fat health, you should look beyond the number on the scale and also track your waist circumference, body fat percentage, and muscle mass," Park said. "Combining a well-managed diet — including healthy unsaturated fats — with aerobic exercise, strength training, and more daily walking will all contribute to better metabolic health."