New study challenges theories about weight loss, fat and calories

10/11/2022

Yet another study the Dietary Science Foundation has supported has been published; this time a study of diet and obesity. The results go against several established theories in the area. Participants lost a substantial amount of weight despite an almost normal calorie intake. The amount of fat or carbohydrate in the diet made no difference as far as weight reduction and the study gives reason to question whether saturated fat really is a significant cause of fatty liver.

The Dietary Science Foundation has good news once again! The first results of the study of diet for obesity that we helped fund in 2018 have been published in the scientific journal Clinical Nutrition. We supported the study as it was designed to examine how the amount and quality of carbohydrates influences weight loss, and how saturated fat affects the body. Now we know how it went! Let’s start with some background information.

Two different low-fat diets and one low-carbohydrate diet tested

In the new study, which was carried out in Bergen, Norway, 193 very overweight people aged 20-55 were allotted to three different diets: a strict low-carbohydrate diet rich in saturated fat; a traditional low-fat diet with a lot of wholemeal flour; and a cellular low-fat diet where ingredients such as potatoes, fruit and grains were eaten in their whole foods form with no grinding, pressing or milling. All of the diets were rich in vegetables and other natural foods. The amount of added sugar was minimal. Participants consumed what was a close to normal amount of energy: 2,000 calories per day for women and 2,500 calories per day for men.

“What’s interesting is that all the diets had the same good effect. Participants who increased their fat intake showed an even greater reduction in waist circumference after six months than those who increased their fiber intake,” says Simon Dankel, professor at the University of Bergen, who led the study. 

The percentage of fat or carbohydrates did not matter

The study challenge several established theories in the field of nutrition. For example, the proportion of fat or carbohydrates in the diet had no significant effect on weight loss. The study also showed that the amount of liver fat decreased significantly in all groups, even in the low-carb group that consumed a lot of butter and cream. Previous studies from, among others, Uppsala University have indicated that saturated fat is bad for the liver, but this study does not support that hypothesis. Instead, it confirms results from a previous study funded by the Dietary Science Foundation, where both a strict low-carbohydrate diet and intermittent fasting reduced the amount of fat in the liver more effectively than conventional treatment. 

What made participants lose weight?

Now to an important question. How could the participants lose so much weight without a drastically restricting calorie intake? 

“If you reduce your intake of sugar and ultra-processed food and primarily eat food based on high-quality ingredients it doesn’t seem to make much difference what you eat,” according to Simon Dankel. 

One weakness: a high drop-out rate

One weakness in the study from Bergen is a high participant dropout, presumably because the program was very demanding. Regardless of that the results confirm what other similar studies such as the DIETFITS study in the USA have shown.

“Avoiding sugar and fast-acting carbohydrates appears to allow many severely overweight people to lose weight, but the study was done on relatively young people. Things might be different in an older group,” says Kerstin Brismar, professor of diabetes research at Karolinska Institutet and chairman of the Dietary Science Foundation’s scientific advisory board.

Isn’t this good news? If you want to know more about the study, you can read a more detailed analysis via this link.

There is more to learn from the Bergen study

In addition to measuring weight, abdominal circumference and changes in liver fat, the researchers in Bergen are mapping in detail how the participants’ blood fats were affected by the dietary change. In addition, an analysis of intestinal flora is underway. We eagerly await the results of this work.

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