FAST diet: study shows promise

Posted on Tue, 12 Nov 13

Intermittent fasting is gaining popularity as a weight loss strategy and a new clinical study found impressive effects within just 12 weeks.

Intermittent or alternate day fasting involves a reduced calorie intake balanced with unrestricted eating on alternate days. A popular approach is the 5:2 strategy which adheres to 2 low calorie days per week based on low energy density foods such as whole grains, vegetables, fruits and lean meats.

Despite its popularity only a few studies have explored the effects of this dietary approach. In a new study 32 people were randomized to either an intermittent fasting diet (FAST diet) or a control diet for 12 weeks. The FAST diet group consumed 25% of their baseline energy needs on the fast day (24 h), and then ate freely on each alternating day.

After 12-weeks the FAST diet resulted in a reduction in body weight of an average 5.2 kg and a reduction in fat mass of 3.6 kg (see figure 1).

Figure 1: Changes in body composition with alternate day fasting (ADF) versus control.

The FAST diet also significantly reduced triglycerides, inflammation (C-reactive protein) and favourably influenced other metabolic risk markers (LDL particle size, plasma adiponectin, and leptin). 

“In summary, these preliminary findings suggest that ADF is a viable weight loss strategy for normal weight and overweight individuals wishing to lose a moderate amount of weight (5–6 kg) within a relatively short period of time (12 weeks)” concluded the study investigators. “It is our hope that this preliminary data will be utilized to design larger-scale longer-term trials with similar objectives, in normal weight and overweight participants undergoing ADF.”

Reference: 

Varady KA, Bhutani S, Klempel MC, Kroeger CM, Trepanowski JF, Haus JM, Hoddy KK, Calvo Y. Alternate day fasting for weight loss in normal weight and overweight subjects: a randomized controlled trial. Nutr J. 2013 Nov 12;12(1):146. [Epub ahead of print]