Feast or Famine: What’s the Deal With Alternate-Day Fasting?

You might have heard of standard intermittent fasting but have you ever tried your hand at alternate-day fasting? It’s a style of intermittent fasting that involves “modified” fasting. This means you fast every other day, which means consuming fewer kilojoules.

The basic idea around alternate-day fasting is that you can eat what you want on one day and then the next day, you fast and consume fewer kilojoules — hence why this is also known as the “feast or famine diet”. According to Healthline, the most popular way of executing this eating pattern is eating roughly 2,000 kilojoules on your fasting days — the recommended intake for an adult is roughly 8,700 per day so this is a drastic reduction.

What are the benefits of alternate-day fasting?

Generally speaking, alternate-day fasting is largely used for weight loss purposes. But, alternate-day fasting is said to also assist in changing body composition, the management or prevention of type 2 diabetes while also helping improve heart health and boosting cell breakdown and regeneration.

As for the weight loss element, studies have shown that engaging in every other day restriction is no more effective than traditional daily kilojoule restriction. According to Healthline, both of these forms of kilojoule restriction have been shown to be equally successful in promoting weight loss and reducing harmful belly fat.

So, while this eating pattern can help with weight loss, it hasn’t been scientifically proven to be more effective than other forms of kilojoule restriction.

What are the downsides to alternate-day fasting?

Unsurprisingly, research has found that many people who engage in alternate-day fasting reported feeling uncomfortably hungry and irritable on fasting days and, according to Harvard Health Publishing, didn’t get accustomed to these discomforts with time.

In the same study from 2005, researchers found that participants who were engaging in alternate-day fasting actually ate more on fasting days and less on feasting days, which, by the end of the study, meant they were consuming food similarly to a group who were engaging in traditional kilojoule restriction.

For Dr Monique Tello, a practising physician at Massachusetts General Hospital, director of research and academic affairs for the MGH DGM Healthy Lifestyle Program and clinical instructor at Harvard Medical School, alternate-day fasting isn’t an eating plan she would recommend.

“Usually at this point we say something like ‘more studies of this approach are needed,’ but I won’t. There’s already plenty of evidence supporting a common-sense lifestyle approach to weight loss: ample intake of fruits and veggies, healthy fats, lean proteins, and plenty of exercise. From apples to zucchini, there are over a hundred ‘real’ foods you can eat endlessly, enjoy, and yes, still lose weight,” Dr Tello wrote for Harvard Health Publishing.

“I would advise against spending any more money on fad diet books. Or processed carbs, for that matter. Rather, hit the fresh or frozen produce aisle, or farmer’s market, and go crazy. Then go exercise. Do that, say, for the rest of your life, and you will be fine.”

Before beginning an eating pattern like alternate-day fasting, talk to your GP to make sure it is healthy for you.