Weighing up the Fast Diet

There are things that suit being round.

Take wheels for example. If wheels were any other shape, they wouldn’t work.

Hats, steering wheels, and watches have all used the round shape brilliantly over the years.

Humans are an exception.

We were never intended to be round and although the reasons for developing roundness are complex and worthy of compassion, being round can lead to an early death.

When I was 20, I could eat a takeaway meal at midnight and still be thin in the morning. Now aged over 30, I can’t eat a whole takeaway and need to loosen my trousers at the end of a meal.

Over years I was slow to notice the weight increasing. I didn’t do myself any favours by eating the 3rd tier of my wedding cake (7 pounds gained on that alone).

Weight gain is like a management project, it creeps. I tried various diets but success always ended with weight sneaking back on.

In January 2013 a health check sounded my alarm bells:

  • Blood Pressure: 139/90 (borderline high)
  • Cholesterol: 7.63 (high)
  • BMI: 26.3 (unhealthy)
  • Waist: 40 inches (round but hidden by a shirt and tie)
  • Neck: 17 inches

Wondering what to do, I came across a news update about a TV programme I had seen the previous summer.

The BBC’s science strand Horizon did a feature on Intermittent Fasting. It had become an internet sensation. Then I realised. That’s what I’ll do, the Fast Diet.

What is the Fast Diet (AKA 5:2)?

The Fast Diet is a version of Intermittent Fasting and it means reducing your calorie intake two days per week to 25% of your average — which means 500 calories for a woman and 600 for a man. On non-fast days you eat without over-compensating i.e. no bingeing.

But there are various styles of Intermittent Fasting to choose from:

The 16/8 — involves fasting for 16 hours every day. You’ll restrict your eating to an eight-hour window.

Alternate Day — is when you apply the calorie restriction during alternate days instead of two days a week.

Eat-Stop-Eat — involves eating nothing for a full 24 hours, eating the next day, then fasting again.

Unlike other forms of dieting, intermittent fasting has the advantage of no complicated rules and no daily chore of calorie counting.

Fasting is one of the most powerful things you can do to your body. It also has a history steeped in ancient practice and religion.

Dr. Michael Mosley and Mimi Spencer have popularised the approach through the Horizon programme and the follow-up book, The Fast Diet — The Simple Secret of Intermittent Fasting: Lose Weight, Stay Healthy, Live Longer (available on Amazon). The official site still attracts a community of followers five years after the original programme. (www.thefastdiet.co.uk).

5:2 is Mosley’s revised version of Intermittent Fasting aimed at harnessing the benefits of fasting with a routine that’s sustainable for the long term. The benefits Mosley outlines are:

  • It makes us think about when and what we eat
  • There are no complicated rules
  • No daily chore of calorie counting
  • Weight tends to stay off
  • Can reduce risks of diabetes, heart disease and cancer.

Evidence is mixed and not always based on human trials.


I didn’t undertake preparation. I thought about when to start, scratched my head and decided to do it.

My first attempt began the following Monday. Between February and August 2013 I lost 18 pounds and, with a few ups and downs, the weight stayed off.

As for recommended recipes, an easier way is to try porridge or low calorie / high protein meals from your favourite supermarket. Hunger is a pain and arriving home from work the last thing on your mind is taking 90 minutes to roast a chicken.

After one year, results were modest but encouraging:

  • Blood Pressure: 160/82 (more work needed)
  • Cholesterol: 6.1 (borderline but going in the right direction)
  • BMI: 24 (healthy)
  • Waist: 37 inches (anti-diabetes)
  • Neck: 16½ inches (needed new shirts)

The modest results are proof that intermittent fasting is not a cure-all but could be significant as part of an overall lifestyle change. To improve results, I increased exercise activities.

With increased exercise, I improved my blood pressure to an average of 135/85, much to the satisfaction of my family doctor. I would like to make further improvements since mid-morning spikes offset lower blood pressure readings during sleep and other times of the day. Too much coffee perhaps?

The 5:2 approach to intermittent fasting is transformational but you need to augment it with an active lifestyle and balanced diet.

Fast Diet Challenges

Holidays — Vacations challenge the fasting habit because you fall out of routine. With fasting, you choose when and when not to do it, so if you stop during holidays, that’s fine.

Tiredness — Energy dips towards the end of the work day. I remedy this by going on a walk at lunchtime and eating fruit.

Low Mood — Don’t fast when you’re feeling low. If you start off on a fast day, and give in to temptation, you can try again when you feel up to it.

5 Reasons For Fasting

  1. Choice — I fast on Mondays and Wednesdays but have changed it from time to time as the needs arise.
  2. Benefits — fasting improves learning and memory, reduces cholesterol, improves the body’s sensitivity to insulin and therefore the ability to breakdown fat.
  3. It’s a way of life — 5:2 is now routine during the week. It’s a lifelong change and if the evidence is right, a longer-life change.
  4. Sustainable loss — if you adopt fasting as a way of life rather than a quick fix diet, you’re more likely to achieve lasting results.
  5. Patience — When I booked my last holiday flight the airline tried to up-sell onboard meals — “it’s a 3 hour flight so don’t go hungry” they declared. With dinner at 7pm and nothing until lunch the next day (17 hours) I could fly to USA and back without a meal.

2 Reasons Against Fasting

  1. Lowered Metabolism — As your metabolism slows during a fasting day, you’ll feel colder, especially in winter. If this happens, you could compensate by exercising.
  2. Individual Results — Fasting doesn’t work for everyone. A friend tried the 5:2 and didn’t lose weight. As your body and metabolism adjust, you may also find weight returning.

Everybody is different and what works for one may not work for another. But if you’ve never tried intermittent fasting, give the Fast Diet a try. You could transform yourself.

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An older version of this article first appeared on mindbodyandtech.com