Unsaturated fat may prevent abdominal fat accumulation
Obesity has become a catastrophic epidemic problem worldwide. Clearly, poor dietary patterns coupled with sedentary lifestyles are to blame. Obesity is associated with serious negative health consequences including heart disease, diabetes and emotional problems. Of great concern to people concerned about weight control problems is the accumulation of abdominal fat, which also causes serious problems with their appearance. New research shows that eating unsaturated fats can help prevent abdominal fat accumulation.
Excess ectopic fat storage can be a serious problem which is linked to type 2 diabetes, reports the journal Diabetes. Researchers investigated liver fat accumulation and body composition during overfeeding with saturated or polyunsaturated fat. In this study thirty-nine young and normal-weight individuals were overfed muffins which were high in saturated fat (palm oil), or polyunsaturated fat (sunflower oil) for 7 weeks. MRI was than used to assess liver fat, visceral, subcutaneous abdominal , and total adipose tissue, pancreatic fat, and lean tissue.
Each of the groups in this study gained similar weight. However, saturated fat markedly increased liver fat in comparison with polyunsaturated fat and caused a 2-fold larger increase in visceral fat than than polyunsaturated fat. It was observed that conversely polyunsaturated fat caused a nearly 3-fold greater increase in lean tissue than saturated fat. The researchers concluded that overeating saturated fat promotes hepatic and visceral fat storage. However, excess energy from polyunsaturated fat may instead promote lean tissue in healthy people.
It has been found in this new research that saturated fat builds more fat and less muscle than polyunsaturated fat, reports Uppsala University in a discussion of this research on Feb. 24, 2014. It has been highlighted that this is the first study on people which shows that the fat composition of food not only influences cholesterol levels in the blood and the risk of cardiovascular disease, but it also determines where the fat will be stored in the body.
In this study 39 young adult men and women of normal weight ate 750 extra calories daily for seven weeks. The researchers set a goal for the participants to gain three per cent of their starting weight. The extra calories were consumed in the form of muffins which had a high fat content, and which were baked in the lab by Fredrik Rosqvist, a doctoral candidate and first author of the study. Each of the diets contained the same amount of sugar, carbohydrates, fat, and protein. The only difference between the muffins was the type of fat they were made with. Half of the subjects consumed surplus calories in muffins from polyunsaturated fat (sunflower oil), while the other half got their extra calories from saturated fat (palm oil).
Although there were comparable weight gains between the two diet groups, the extra consumption of saturated fat caused a markedly greater increase in the amount of fat in the liver and abdomen in comparison with the extra consumption of polyunsaturated fat. Furthermore, the total amount of body fat was found to be greater in the saturated fat group. Also, the increase in muscle mass was observed to be three times less for those who ate saturated fat in comparison with those who ate polyunsaturated fat.
What this means is that gaining weight on excess calories which were from polyunsaturated fat caused greater gain in muscle mass, and less body fat than overeating a similar amount of saturated fat. Because the majority of us are in positive energy balance, and consequently gain weight slowly but gradually over the course of time, these results are highly relevant for most populations in the West.
Ulf Risérus, associate professor at the Department of Public Health and Caring Science and director of the study, said, "Liver fat and visceral fat seems to contribute to a number of disturbances in metabolism. These findings can therefore be important for individuals with metabolic diseases such as diabetes." Risérus has gone on to explain that if the findings dealing with increased muscle mass following consumption of polyunsaturated fat can be confirmed in further studies, this will potentially be particularly interesting for many elderly people, for whom maintaining muscle mass is very important in preventing morbidity.
In a consideration of the risk of developing diabetes and cardiovascular diseases, it appears more important where in the body the fat is stored than how much fat the body actually has. There is a close association with increased risk for developing type-2 diabetes with visceral fat, along with a high proportion of fat in the liver. New drugs and dietary strategies should therefore target these fat depots. Interestingly, in a number of studies it has been indicated that a higher consumption of polyunsaturated fats from plant oils and nuts is associated with a lower risk of type-2 diabetes, however the reasons for this have not been clear.
In this study a potential explanation for such an association is proposed. It appears that polyunsaturated fatty acids can affect fat distribution in the body in a more favorable way than saturated fats, probably by regulating increased energy combustion or decreased storage of visceral fat in association with calorie-rich diets.
It also appears to the researchers that over-consumption of saturated fats seems to be able to “turn on” certain genes in fatty tissue which increase the storage of fat in the abdomen and at the same time interfere with insulin regulation. And instead polyunsaturated fats appear to “turn on” genes in visceral fat which in turn are associated with reduced storage of fat and improved sugar metabolism in the body. More research is however needed to understand how this occurs in people.
These new findings suggest that the fat composition of the diet, in the long term, might play a significant role in preventing obesity associated disorders, such as type-2 diabetes, at an early stage, before being overweight actually occurs. Risérus says this is important because at this time we do not have preventive treatments for fatty liver and visceral fat. These new findings also support international dietary recommendations which include the new Nordic nutritional recommendations, which, among other things, recommend replacing some saturated fat such as that which comes from meat, butter and palm oil with unsaturated fats from plant oils and fatty fish.
In spite of deepening concerns about the obesity epidemic and associated serious health hazards, I find that a lot of people are continuing to ignore good dietary advice. Therefore, even though the findings in this study are significant, that does not mean suddenly more people will start taking good dietary advice more seriously. It will take much more aggressive educational initiatives in a creative manner to get more people to desire to eat healthier foods while being more active in order to avoid obesity. The message about the potentially great advantages of eating more unsaturated fats and less saturated fats should be shared with patients during counseling about healthy diets by their physicians.