There certainly are health risks associated with prolonged fasting, and – as a dietitian and nutritionist – it’s not something I recommend very often.
However, as one person’s meat can be another’s poison, calorie restriction methods like intermittent fasting can suit certain people. Weight loss can be achieved by creating an energy deficit – by eating less over spaced out periods – but this strategy is only ideal for overweight and obese individuals.
Anyone deciding to intermittently fast does so at the risk of developing a nutrient deficiency. Which, of course, can lead to a host of serious health problems, ranging from anaemia to vitamin and mineral deficiencies. Skipping meals and severely limiting calories is particularly contraindicated for people who are pregnant, diabetic or taking regular medication that requires food.
As you’d probably expect, the practice of intermittent fasting goes a long way back. The simple process of pushing out the time between meals dates back to at least the seventh century, when Muslim people first began practicing the holy tradition of Ramadan, and possibly even before then. From my experience, it's only been over the last few years that people have started using intermittent fasting as a dieting technique.
If you are considering intermittent fasting, it’s important that you discuss it with your doctor first to determine whether you meet the criteria. If you do, the appropriate style of fasting –including the popular 16:8 method – then depends on your lifestyle and level of activity.
Glenn Harry, accredited practicing dietitian and nutritionist at Spectrum Nutrition and Dietetics