The global obesity crisis has spurred on studies looking at various ways to combat this condition. A recent Korean study investigated the impact of a mild calorie-reduced diet on different obesity biomarkers, such as visceral fat and fatty acids.
Visceral fat has been linked to chronic health diseases including type 2 diabetes. Unlike subcutaneous fat, found directly beneath the skin, visceral fat is found deeper in the abdominal cavity, often around important organs, such as the liver. Overweight individuals tend to carry excess visceral tissue fat, which makes them more susceptible to these chronic diseases. In addition, they tend to have higher levels of fatty acids circulating in the blood, which are also markers of chronic disease risk. Although investigators have shown an association between visceral fat levels and plasma fatty acid profiles in overweight individuals, they have not yet managed to show how these profiles are affected by weight loss.
How Does Calorie Restriction Affect Weight Loss and Visceral Fat?
A Korean study recently published in the Nutrition Journal looked at how weight loss influences fatty acids and two desaturase enzymes. They recruited 75 overweight adults between 20 and 60 years old with high levels of visceral fat, but who did not suffer chronic diseases, such as diabetes or hypertension. The participants were randomly divided into two groups: the control group, who were asked to continue with their usual diet and physical activities; or a calorie-restricted group, who were asked to reduce their daily calorie intake by 300 kCal, which is equivalent to one bowl of steamed rice. The participants were asked to record their diets and to provide blood samples to determine their fatty acid profile at baseline. Three-day diet diaries were also recorded at six and 12 weeks. At the 12-week study conclusion, the investigators recorded various physical measurements and took more blood samples.
Calorie Reduction Led to Weight Loss
The calorie-restricted group experienced significant changes in 22 variables compared to the control group. Unsurprisingly, the calorie-restricted group lost 15% of visceral fat and 3.4% body weight during the 12-week study. The levels of all fatty acids decreased as did the levels of C16 ∆9 desaturase, which is an indicator of insulin resistance and abdominal obesity. In contrast, levels of ∆5 desaturase increased, corresponding to a decreased risk of type 2 diabetes and insulin resistance. Changes in the visceral fat levels also had positive effects on serum insulin and triglyceride (a type of fat found in blood) levels, systolic blood pressure, and waist circumference.
As this small study was limited to non-diabetic Koreans who were overweight, there is a possibility that these results will not be seen in other populations to the same degree. Despite this limitation, these results show that reducing the levels of fatty acids in overweight individuals has many positive health benefits. What is more, this can be achieved simply by moderately reducing the amount of calories we consume on a daily basis. This study confirms the health benefits of even mild calorie restriction.
Written by Natasha Tetlow, PhD
Reference: Lee YJ, et al. Effect of weight loss on circulating fatty acid profiles in overweight subjects with high visceral fat area: a 12-week randomized controlled trial. Nutrition Journal. 2018; 17:28. DOI: 10.1186/s12937-018-0323-4.