Replacement of 60% of the saturated fat in a typical British diet by an equivalent number of calories of other dietary fats, and avoiding 60% of dietary cholesterol, would reduce total cholesterol in the blood by 10-15% (about 0.8 mmol/litre), with low density lipoprotein (LDL) cholesterol (the unhealthy cholesterol fraction) accounting for about 80% of the reduction. This was the main conclusion of a statistical overview (meta-analysis) of 72 published reports (involving 129 groups of volunteers participating in 395 experiments in metabolic wards) of controlled dietary intervention studies. Replacement of 10% of the saturated fat calories by complex carbohydrates (fibre) also produced a fall in total cholesterol; again, the major reduction was in the LDL form.