211 5 4 the role of diet in related disease health associations excess energy intake obesity nhmrc defines as a bmi greater than 30 kg m 2 see box genetic and environmental factors are likely to be involved aetiology 147 which has been described heterogeneous disorder with multiple aetiologies hence risk 148 is result being expenditure for sustained period often years determined by sum resting metabolic rate level physical exercise loss weight possible if activity increased food decreased although difficulties many obese people changing their behaviours well recognised 149 there growing evidence that total dietary fat levels positively associated an prevalence 87 only weak effect on satiety may contribute passive over consumption such flavour texture need considered managing variety found
