Energy balance

Intermittent Energy Restriction (IER) combined with High-Intensity Interval Training (HIIT) produces greater reductions in body weight, body fat percentage, waist circumference, and hip circumference compared to Continuous Energy Restriction (CER) combined with HIIT in overweight/obese adults, although the difference is not statistically significant in a 4-week trial.

If you are overweight or obese, combining High-Intensity Interval Training (HIIT) with an Intermittent Energy Restriction (IER) diet may help you lose more weight and body fat than a standard daily calorie-restricted diet over a short period. Specifically, eating only 30% of your daily calorie needs on two non-consecutive days a week, while eating normally on the other five days, resulted in nearly double the weight loss (4.6 kg vs 2.5 kg) compared to eating 70% of your needs every day. Although the difference wasn't statistically significant in this small 4-week study, the trend favors IER for body composition improvements.