In Northern Sweden, the incidence of heart disease in the 1970s was higher than any other region in the country. Furthermore, men in this area had some of the highest prevalence of cardiovascular disease in the world.
As a result, in 1985, the Vasterbotton Intervention Program (VIP) was set up in order to reduce fat intake and decrease cholesterol levels by offering diet advice, cooking demonstrations, healthy information, better food labeling, and health examinations and counseling.
In this study, researchers from Umea University, University of Gothenburg, in collaboration with The National Board of Welfare, assessed 25 years worth of data from VIP and combined it with data from the WHO MONICA project which monitors cardiovascular disease risk factors.
According to the researchers, by 1992 men had reduced their fat intake by 3% and women by 4% due to the impact of the VIP, and figures remained stable until 2005. In addition, cholesterol levels had also decreased as, for example, more people switched from butter to low fat spreads.
However, with the growing popularity of low carbohydrate, high fat diets in the last decade, the researchers found that saturated fat intake began to increase substantially after 2005, returning to levels above those in 1986. As a result cholesterol levels also began to increase even though cholesterol lowering medications were introduced.
Professor Ingegerd Johansson, lead author of the study, said:
"The association between nutrition and health is complex. It involves specific food components, interactions among those food components, and interactions with genetic factors and individual needs. While low carbohydrate/high fat diets may help short term weight loss, these results of this Swedish study demonstrate that long term weight loss is not maintained and that this diet increases blood cholesterol which has a major impact on the risk of cardiovascular disease."