Can people make healthy changes to their diet and maintain them in the long term? A review of the evidence

A diet high in saturated fat and low in fibre, fruit and vegetable intake is a risk factor in chronic conditions and in overall mortality. Current records show little long term dietary change in the general population. This review examined evidence for long term successful dietary changes in the daily intake of fat, fruit, vegetables and fibre. Eight randomized control trials with 17 intervention arms were included. There were 62,565 participants (89% women) randomized to intervention or active control group. Participants in most of the intervention groups were able to make changes in the daily intake of fat (reduction range: 1.6–13.7%) fruit and vegetables (increase range: 0.2–4.6 svgs/day) and fibre (increase range: 0.9–13.5 g/day) as measured at 12 months. The magnitude of these changes diminished thereafter with each consecutive year following intervention with the exception of Polyp Prevention Trial where the changes were maintained for 4 years of trial duration. A well designed intervention motivated participants to make and maintain successful dietary changes in terms of reduction of daily fat intake and increased intake of fruit, vegetables and fibre over the course of 12 months. The differences in dietary intake as compared with baseline diminished steadily with each subsequent year of intervention unless the intervention programme remained highly intensive.