A previous study has found that the consumption of a high fat, low carbohydrate meal results in increased feelings of calmness, friendliness and an increase in subjective energy levels in comparison to a low fat, high carbohydrate meal. The purpose of this study is to investigate whether a high fat, low carbohydrate diet for a longer duration (of 2 weeks) can enhance or sustain these changes in comparison to a low fat, high carbohydrate meal.