Randomized clinical trial comparing the effectiveness of two dietary interventions for patients with hyperlipidaemia.

1. Intervention trials in free-living populations have shown relatively small reductions in risk factors for cardiovascular disease, including lipid levels, and have led some to question whether diet is an effective treatment for hyperlipidaemia. However, behaviour change is a complex process and it is possible that standard intervention methods fail to motivate people sufficiently to comply with dietary advice.2. This study applied motivational interviewing, a style of behaviour change counselling, to dietary education for people with hyperlipidaemia. One-hundred and twenty-one patients with hyperlipidaemia who had been referred to a hospital dietetic department for dietary advice were randomized to receive either standard or motivational dietary interventions for a period of 3 months. Outcomes assessed included dietary knowledge, stage of change, dietary intakes, lipid levels and body mass indices. 3. From baseline, both methods of dietary intervention resulted in self-reported changes in dietary habits and knowledge, statistically significant reductions in intake of total fat (from 32.8% to 28.4%), saturated fat (from 11.4% to 9.2%) and energy intakes [-239 kcal (-999.98 kJ)/day], and in body mass indices (-0.45 kg/m2). Serum cholesterol did not change significantly in either intervention group.4. Motivational and standard dietary interventions achieved statistically significant changes in reported dietary knowledge and behaviour, and led to a reduction in body weight, but not serum cholesterol. Whether this lack of effect is real or due to subjects overestimating true dietary change cannot be determined. Change in body weight was associated with a reported change in energy intake; this provides some support for there having been a real change in intake.