Trial lecture - time and place
See Trial Lecture
Adjudication committee
- First opponent: Professor Anne Raben, University of Copenhagen, Denmark
- Second opponent: Research director Helle Margrete Meltzer, Norwegian Institute of Public Health, Oslo
- Third member and chair of the evaluation committee: Professor Haakon Eduard Meyer, Institute of Health and Society, University of Oslo
Chair of defence
Associate Professor Elisabeth Qvigstad, Institute of Clinical Medicine, University of Oslo
Principal Supervisor
Adjunct Professor Serena Tonstad, Loma Linda University, California, USA
Summary
Dietary modification is a cornerstone in the prevention and treatment of obesity, metabolic risk factors and cardiovascular disease. Long-term adherence to conventional weight-loss diets is limited while intermittent fasting has risen in popularity.
Clinical trials have shown that reduction in LDL-C reduces cardiovascular events. Saturated fatty acids (SFA) increase LDL-C while polyunsaturated fatty acids (PUFA) lower it. However, the lipid response may be affected by the presence of obesity, and nutritional recommendations may not always “fit” the obese segment.
Study I: We compared the effects of intermittent energy restriction (IER) versus continuous energy restriction (CER) on weight loss, maintenance, cardiometabolic risk factors and nutritional composition, in adults with abdominal obesity at high cardiovascular risk. We randomized 112 participants with BMI 30-45 kg/m2 to IER or CER for 1-year. The IER group was advised to consume 400/600 kcal (female/male) on two days, and eat as usual the remaining five days a week. Participants in the CER group were advised to reduce energy intake evenly on all 7 days a week. Based on dietary records both groups reduced energy intake by ~27%. IER and CER resulted in similar weight loss, maintenance and improvements in cardiovascular risk factors after 1-year. CER was associated with more favorable changes in nutritional composition (in regard to intake of fruit and vegetables, fiber, vitamin C and sugar) compared to IER.
Study II: We compared the effect of substitution of PUFAs for SFAs on LDL-C and apolipoprotein B in normal weight (BMI ≤25 kg/m2) and obese (BMI 30-45 kg/m2) subjects with elevated LDL-C. We randomly assigned 83 men and women stratified by BMI, to PUFA-diet enriched with oil-based margarine or SFA-diet enriched with butter for 6 weeks. The effect of replacing SFA with PUFA was dependent on BMI, with lesser improvements in atherogenic lipids in obese than in normal weight individuals with elevated LDL-C.
Additional information
contact the Research Support staff