IT IS RARE to meet someone in midlife these days who hasn’t tried fasting. While fit celebrities and high-flyers may see it as a way to stay in optimum health, boost their brain power, and stay youthful, the rest of us see it as an effective way to lose and maintain weight. If you haven’t yet tried the 5:2 (consuming 500-600 calories two days a week, eating normally the rest of the time) or the 16:8 (consuming all your daily meals within an eight-hour window), you probably know someone who is evangelical about the weight they have lost — and kept off — through one of these approaches.
In a world of faddy diet trends, what sets fasting apart is the growing scientific evidence that it works. Time-restricted eating can also slip relatively seamlessly into our lives. But it is not a magic bullet; it often works for people because they can choose the fasting rules that suit them. From our fifties onwards, our body’s requirement for calories declines — another reason fasting is more straightforward to adopt as we age. Age, hormonal changes, and a natural decline in muscle mass all affect our energy requirements. We need 100-300 fewer calories daily, and intermittent fasting is one way of achieving that deficit.
Beyond weight loss, there are other reasons fasting is so appealing to midlifers. Studies have shown that it produces health gains ranging from improved cognitive function, gut health, sleep, and blood sugar control to slowing the ageing process by helping the body flush out damaged cells and regenerate healthier ones — a process called autophagy — potentially boosting longevity. In a paper published last year, Valter Longo, a professor of gerontology and biological sciences and director of the Longevity Institute at the University of Southern California, says that fasting helps to control and even reduce levels of insulin, C-reactive protein, insulin-like growth factor 1, and cholesterol, all of which are markers for severe disease.
We are not designed to eat for an entire 24-hour cycle, and your body and digestive system need a break; intermittent fasting is one way of doing that. Not that fasting is easy — many find that the 16:8 hunger pangs in the first week are unbearable, although they pass by week three — nor is weight loss guaranteed. Much depends on how you choose to break each fast; if you eat lots of ultra-processed and refined foods, you will slow any potential effects, whereas consuming plenty of pulses and whole grains, vegetables, nuts, and olive oil will contribute to weight loss and health gains.
Here’s what to try:
12:12 — The Beginner’s Fast
If you are new to intermittent fasting, you must gradually ease yourself in. The best way to do it is to set a daily “eating window” that is manageable. Twelve hours is a good starting point. Once you can comfortably manage eating and fasting for 12 hours a day, start to extend the fasting segment by an hour or two to eat within 10 hours and fast for 14 (14:10). The natural beauty of so-called time-restricted eating, or TRE, is that it can be worked around your lifestyle and body clock. If you feel you need to eat breakfast, you can schedule the window to start and finish earlier than if you don’t wake up hungry.
16:8 — The Midlife Fast
It has more evidence than other fasting methods in published studies showing its effectiveness for weight loss, midlife weight maintenance, and health benefits. Its appeal is that it is doable for most of us — the rules are to consume your daily calories within an eight-hour window, leaving 16 hours without food (although you can have water, black coffee, and calorie-free drinks). You can select a fasting window that suits you. A Nutrition and Healthy Ageing journal study suggested an eating window of 7 am to 3 pm is optimal, although shifting later is fine if you wouldn’t usually have breakfast. Finishing your last meal by 7 pm is best for avoiding a sluggish metabolism. How it fits into your lifestyle is more important than the timing of the eating window itself. It’s got to be something that works well for you.
Ultimately, 16:8 works like any other intermittent fast, meaning fewer calories are consumed without actually having to count them. In one study, 16:8 dieters ate 350 fewer calories a day than study participants following other forms of fasting diet and lost 3 per cent more body weight after 12 weeks.
The 5:2 — The Classic Weight-Loss Fast
On the other five, you eat about 500 calories twice weekly and what you like (within reason). Despite a lack of specific studies on the benefits of 5:2, plenty of science shows general metabolic and weight-loss benefits for intermittent fasting. One review of 40 studies showed that it can help people lose up to 11 pounds in ten weeks. Twice-weekly fasts, however, are only for some. A 2021 study that compared its effects with standard advice on calorie counting and healthy eating in 300 overweight adults showed that three-quarters of people managed to stick to the 5:2 rigidly for six weeks but struggled after that, with only one-third following it six months later.
