I’ve written briefly about the 5:2 diet recently, and thought that this study summary of the ADF diet might prove useful to those of you considering either 5:2 or ADF.
Here you can find the original journal article from The American Journal of Clinical Nutrition, detailing results of ADF (alternate day fasting). ADF means eating whatever you like on ‘feed days’ followed by fasting (600 calories for men, 500 calories for women) on alternate days.
This was the fourth ADF trial ever conducted. The first two were in normal-weight men and women and showed that a 2-3 week ADF programme reduced body weight by 2.5% on average. The third trial was for overweight adults over an 8 week period and concluded in weight loss of 8% on average.
This study looked at ‘the degree of weight loss that could be achieved by ADF during a period of controlled food intake compared with a period of self-selected food intake combined with dietary counsel[l]ing’. 16 obese adults took part in the 10-week trial (12 women and 4 men). After the study, systolic blood pressure decreased, total cholesterol decreased, body fat decreased and HDL cholesterol remained the same. Inclusion criteria for the study were: age 35-65, BMI between 30 and 39.9, stable weight for three months before the start of the study, lightly active lifestyle (less than three hours per week of light intensity exercise), no history of cardiovascular disease or diabetes and not taking any weight-loss lipid.
The trial was split into three phases:
Phase 1 (2 weeks) – those on the trial kept their weight stable by eating and exercising as normal, under their own control.
Phase 2 (4 weeks) – this consisted of a controlled ADF period where subjects were given a calorie-restricted meal on each fast day and ate a normal diet chosen by the study coordinators on the other days. All meals were prepared at the Human Nutrition Center in Chicago. All fast day meals were eaten between noon and 2pm to make sure all participants had the same fasting time. Participants were also allowed to consume energy-free drinks, tea, coffee and sugar-free chewing gum. They were all encouraged to drink lots of water.
Phase 3 (4 weeks) – This was the same as Phase 2, but participants could choose what food they ate on ‘feed’ days. This phase also included dietary counselling which helped participants work out personalised fast day meal plans subjects were ‘instructed how to make healthy food choices on the feed days by choosing low-fat meat and dairy options’.
Body weight and percentage body fat measurements were taken at the start of each week. This study was the first study to show that ADF is an effective dietary regime for obese individuals to lose weight. There was a mean weight loss of 5.8% over an 8 week period (an average of 0.68kg per week, per participant over the 8 weeks). Decreases in cholesterol, blood pressure and heart rate were also observed.
The paper notes, ‘An important next step in the ADF field will be to incorporate an exercise program into this lifestyle regimen. Perhaps with the addition of physical activity, HDL-cholesterol concentrations will increase, thus beneficially modulating the entire lipid profile.’