Some people like these plans because it is easier to be all or nothing than to count calories every day.
While weight loss on these diets over time resembles direct calorie counting, researchers have seen other benefits from not eating for long periods of time, especially in the evening and night hours.
For example, if we eat and fast in accordance with the body’s natural rhythm (essentially eating when the sun rises and fast when it goes down), we can expect better hunger control, more body fat loss, and overall weight loss.
However, with alternative fasting days, the days of full fasting can be challenging. Research volunteers have reported feeling extremely hungry and irritable on fasting days, which may explain why we may not follow this pattern for long.
What about people with diabetes who need to keep blood sugar levels from getting dangerously high or low? Experts generally advise against following an intermittent fasting schedule for people with type 1 diabetes or type 2 diabetes who need insulin. Others who should not try extended fasts include people with hypoglycemia (low blood sugar), pregnant or breastfeeding women, and people who are taking medication with food.
The best advice while we wait for more human studies? Before starting an intermittent fast, consult your doctor and an experienced nutritionist to make sure you know what to do.