Unlocking Your Optimal Weight: Insights from a Prolonged Fast

The Science of Exercise and Weight Management

The science is clear: exercise is one of the best things you can do for yourself. It prevents disease, raises energy levels, and improves mental performance. Exercise can significantly boost your productivity. But can you do more than you need? If you’re fairly healthy but want to be more productive, you might be interested in what I discovered from a prolonged fast.

You know the dilemma: how to maintain a healthy weight or, let’s face it, not become overweight. Burning off those extra pounds requires effort and isn’t always enjoyable. I must admit, this is not something I struggle with. As I entered my fifties, my metabolism slowed down. I was forced to adopt what many would consider a strict health regime. This includes a weekly 45-hour fast, time-restricted eating, a healthy diet, regular exercise, and prioritising sleep (since poor sleep can lead to weight gain).

My Journey with Weight Management

For the last five years, I have successfully maintained an assumed ‘optimal weight’ of around 69 kg (152 lbs). Each week, I gradually add a few hundred grams daily, allowing myself some indulgences on the weekend. I know I can afford to go into the red because my 45-hour fast (which starts at 9 PM every Sunday) will bring me back into the black again. The week then repeats. My programme works, and I’m happier and healthier for it.

There is only one drawback: the amount of exercise I have to do. It averages about 1.5 hours per weekday when you factor in getting ready, showering, etc. (longer if I go for a sea swim). This inevitably takes time I could better spend on my business. As my own boss, I can allow for it, not least for its benefits to my mood and performance. However, the net result is that I usually end the week having worked fewer hours—virtually a whole day less—had I not exercised as much. For me, it actually reduces my productivity.

A New Challenge: The Four-Day Fast

In mid-August, an acquaintance inspired me to follow their example and do a four-day fast. This was something I used to do three times a year to give my physiology a good ‘clean out.’ There are many health benefits to fasting, which I won’t delve into here for the sake of brevity. Anyway, I gave it a shot and fasted for 90 hours, giving up only because I find that two or more days can be too detrimental to my sleep. Otherwise, I felt great.

I was fairly active during this period—it was the August Bank Holiday, and I went walking and wild camping. By the end of the nine days, I had only eaten for three of them and lost 3 kg.

Unexpected Results

I assumed I would put the weight back on and return to my usual weight of 69 kg. But surprisingly, I haven't done so, nor do I feel a strong need to. My body seems to have recalibrated itself to a calorie intake slightly lower than before. According to Chat GPT, as a result of a prolonged fast, “the hunger hormone ghrelin (which spikes to signal hunger) tends to adapt downward. So when you do eat again, you feel full sooner, and your hunger cues are weaker than before.” Extended fasting can improve how your body responds to leptin and insulin, two hormones that regulate fullness. Many people notice that food feels more satisfying afterward, so they naturally eat less. Fasting would seem to be the original weight-loss drug, and it’s completely free.

Feeling no great compulsion to eat more and noticing I didn’t feel the need to exercise as much as before, I’ve purposely chosen to keep myself at a lower weight, averaging 68.5 kg (151 lbs) weekly. This seems to be where my body has defaulted, though I’m aware it may creep up, especially as the cooler months approach.

The Positive Upside

The positive outcome of this (aside from saving a little extra money on food and, er… toilet paper!) is that I’m more productive and working more hours because I’m exercising less than before. Instead of a 10 km run, 6 km suffices. Instead of that 30-minute workout, 20 minutes feels enough. I’m not as strong as before and have slightly less stamina, but I’m still plenty active with good energy levels. And I love my food just as much as before. I just don’t feel the need to eat quite as much of it. It’s been a win-win.

Rethinking Optimal Weight

This experience has changed my assumption about what constitutes one’s optimal weight. I’ve realised it is largely subjective and influenced by one’s lifestyle. According to Chat GPT, “a person’s optimal weight is the weight (or weight range) at which they are metabolically healthy, physically functional, and at the lowest risk of disease—often corresponding roughly to a BMI of 18.5–24.9, but ideally adjusted for body composition, genetics, and lifestyle.”

I had believed my ‘optimal’ weight averaged 69 kg based on assumptions about what I needed to do to maintain my health and be productive, including the amount of exercise I needed to do and the food I needed (and would want) to eat over an average week.

Since financial necessity requires me to spend most of my hours at a computer screen, I now realise I’m better off trying to maintain my current slightly lower weight of around 68.5 kg by eating a little less and doing less exercise. This saves me time and helps me be more productive. Had I not done the prolonged fast, I wouldn’t have discovered this or made the necessary adjustments.

Key Takeaways for Personal Growth

So, what lessons can I pass on from this experience?

• For a small proportion of people with good eating habits who aren’t overweight, it can be possible to do more exercise than is strictly necessary, bearing in mind that exercise generally increases appetite.

• Periodically testing your assumptions about what you need to do to be healthy and productive can provide you with new information. This enables you to make lifestyle corrections that may benefit you, such as increased productivity for negligible health costs.

• Doing an occasional prolonged fast, such as three to five days, can help your body recalibrate and be very illuminating. Research suggests it’s very beneficial, though consulting an expert, such as your GP, beforehand is often advised. I would also recommend drinking water with zero-calorie electrolytes while fasting.

  
  

Conclusion: The Balancing Act of Health

In conclusion, working out and maintaining your ideal weight takes effort and discipline. It’s a balancing act based on all the factors specific to you. However, there can be clear benefits and rewards for doing so. Good luck!

Headspace Coaching Plus is healthily obsessed with health and well-being, and always happy to coach others in how they can improve theirs. If this is of interest, get in touch! If you’d like to receive the occasional useful insight, inspiration, and even recipes, please subscribe to my newsletter.