It's easy to assume healthy eating is fairly straightforward – less saturated fat, salt and sugar, more fruit and vegetables. In practice, with hundreds of competing diets and endless conflicting advice online, working out what's genuinely effective for weight loss and maintenance can feel overwhelming.
One approach that's grown in popularity in recent years is intermittent fasting. But what does it actually involve, is it a healthy approach, and can it genuinely support weight loss?
What Is Intermittent Fasting and How Is It Done?
Less a diet in the traditional sense and more an eating pattern, intermittent fasting involves restricting calorie intake during certain windows of time, rather than controlling every meal every day. Many people find this more manageable than a diet requiring constant calorie counting.
The best-known approach is the 5:2 diet – eating normally (meaning healthily, not without limit) for five days a week, and significantly restricting calorie intake on the other two, non-consecutive days, typically to around 500 calories for women and 600 for men. It's generally recommended to have at least one normal eating day between fasting days.
Given the recommended daily intake for a healthy adult is around 2,000 calories, restricting to roughly a quarter of that on fasting days is intended to create the calorie deficit needed for weight loss. Many resources and cookbooks are available to help plan low-calorie meals for fasting days, whether split across two or three smaller meals. The 5:2 approach can also be adapted into a 4:3 pattern, with three restricted days instead of two.
A different approach is 16:8 fasting – eating within an eight-hour window each day and fasting for the remaining sixteen, typically overnight. For example, eating breakfast, lunch and dinner between 10am and 6pm, then eating nothing outside that window.
What Are the Potential Benefits of Intermittent Fasting?
Research into intermittent fasting continues to grow, and its potential benefits extend beyond weight management alone. Some studies suggest links to improved insulin sensitivity, which may help lower the risk of prediabetes and type 2 diabetes, along with potential improvements in some cardiovascular risk factors.
That said, intermittent fasting isn't right for everyone, and it's worth checking with a GP before starting if you:
- Have a history of disordered eating or an unhealthy relationship with food
- Are pregnant or breastfeeding
- Have diabetes and take medication that affects blood sugar
- Have any other underlying health condition, or take regular medication
- Are under 18
For those it's suitable for, intermittent fasting does take some planning and adjustment, and tends to work best as a sustained, long-term pattern rather than something done inconsistently. Many people find it simpler to maintain than constant calorie counting once it's become part of their routine, though as with any approach to eating, it's worth listening to your body and adjusting or stopping if it isn't working well for you.
