(This post follows on from my previous two posts on IF. In post #1 I explained the benefits of fasting, who should avoid fasting, the protocol I personally use. In post #2 I talked about why advice to “just eat less and move more” can be unhelpful and flawed, why fat loss is influenced by more than just “calories in vs calories out” and how low-calorie diets can keep us simultaneously over-fat and over-hungry.)
A lot of people worry about going into ‘starvation mode’ when dieting. This is probably also the number one thing that deters people from trying intermittent fasting.
The fear is, that if we don’t eat for long periods, our bodies will slow down our basal metabolic rate, meaning we’ll use up less energy/calories and the body will cling onto fat.
I described in the last post how low-calorie dieting can reduce the amount of calories we burn, meaning people have to keep cutting calories to achieve weight loss.
Let me explain why this isn’t the case with intermittent fasting.
IF vs Calorie counting – impact on body composition
I myself was concerned about this when I first started fasting. I was worried my body would burn fewer calories and refuse to release fat if it went into ‘starvation mode’ and also that my muscle mass would diminish and I’d lose strength.
This was 8 years ago. Back then there wasn’t a great deal of scientific research to reassure me. But looking around at who was practicing IF made me question my fears. Although IF wasn’t well-known yet, many very fit, strong, lean people were enthusing about the benefits they were gaining from it (Martin Berkhan and Eric Cressey, to name a couple).
So I decided to give it try.
I’m very glad I did!
I didn’t really understand why at the time, but I found I shed fat with no negative impact on my strength and fitness – in fact my progress improved.
The science is still somewhat nascent but there’s growing evidence suggesting fasting actually preserves lean muscle and, so long as we get good nutrition during the “eating window”, our energy expenditure stays high – i.e. we burn fat, we don’t lose muscle, and our metabolic rate doesn’t slow down.
Fasting kept me strong, while shedding fat.
Nowadays, this actually makes perfect sense to me. Think about this…
When we fast, as far as the signals in our bodies are concerned, we are not fuel depleted because we don’t have insulin keeping our fat stores locked up. The body knows our energy supply isn’t low, we have simply switched to our fat stores for fuel which, in the absence of insulin, are freely being released. So there’s no need for the body to slow down our BMR to preserve energy.
Even better, because the body knows we haven’t eaten in a while, it wants to keep us strong, energised and mentally sharp – historically this would have helped us hunt and gather.
One of the ways this happens is via increases in human growth hormone (HGH).
Human growth hormone is basically what it sounds like it is – a hormone that stimulates growth in the body. It helps us grow and maintain muscle, keeps our bones dense and strong and our cells healthy. HRH also helps keep our metabolism functioning well and is thought to make us look and feel younger.
Cardiologists researching the health benefits of fasting found that a 24-hour fast HGH raised by 1300% in women, 2000% in men (yes that is the correct number of zeros!).
In another study, after 4 days of fasting people’s BMR was raised by 12%. Another small study found that even after 22 days of alternate-day fasting there was no drop in BMR… Don’t get me wrong here, I’m not saying you should fast that long, I’m just illustrating the point that fasting doesn’t reduce BMR.
I’m also NOT saying we won’t ever lose any muscle or bone cells at all while fasting, but thanks to autophagy this can actually be a good thing…
Healthy muscle tissue is preserved while aging cells are recycled.
Autophagy Rocks
I first heard the term autophagy just a few years ago in 2016. That was the year the Nobel prize went to Yoshinori Ohsumi for his discoveries around this bodily process which renews and recycles our cells.
Around then, a lot of what I’d experienced with intermittent fasting started making more sense.
The word autophagy literally means self-eating. In this process, which happens when we fast, the body recycles old and damaged cells, using the components to help rebuild new cells.
So, thanks to autophagy, the tissue we lose during fasting is old or damaged and the body recycles it to make new healthy tissue.
This is how fasting keeps our muscles and bones strong and functioning well.
In fact, autophagy helps keep our whole body healthy by destroying diseased cells – including cancerous cells.
Immune cells are regenerated, healing occurs throughout the body, including the brain. It is even thought to help prevent genetic conditions by promoting the expression of “good” over “bad” genes.
It’s easy to see how it follows that a process that replaces old and damaged cells could help keep us young – we’re effectively being renewed and rebuilt!
Even the condition of our skin is improved.
(Interestingly, many experts say people who shed a lot of fat via fasting are left with less loose skin, but I haven’t looked into that much… maybe I’ll come back to it later.)
Opinions differ on how long we need to fast to benefit from autophagy, but most experts recommend at least 24-36 hours.
However, by doing regular shorter fasts, like the 16/8 fasts I regularly practice and keeping the carbs low in our diets can help us get into autophagy sooner during our fasts.
Mental Health
Before I start talking about the practicality of how to get started with intermittent fasting, I want to just quickly explain why I mentioned earlier that IF can be great for our mental health.
Bliss-point foods can actually make us pretty miserable if eaten too often.
Foods containing lots of sugar and fat together (cookies, donuts, cake, chocolate, etc.) stimulate our bodies (and brains) in a way that no natural, unprocessed foods do. The effect this combo produces had been compared to a chemically induced high, sometimes described as a ‘bliss point’.
Opinions vary, but many experts believe some of these bliss-point-inducing foods can be as addictive as heroin. (Personally, I’ve always thought that was bit extreme – but nonetheless, as most of us know only too well, those foods can definitely be very morish and tough to quit once you get in the habit of eating them.)
In the last post I explained how insulin causes intense cravings and constant hunger. Clearly, this alone is not good for mental health, but it doesn’t end there. With that often comes frustration, crankiness, tiredness, peaks and troughs a feeling of being out of control.
Also, blaming others for tempting or not supporting us, or feeling guilty for not having enough willpower can impact on our relationships with others and ourselves.
Sadly because of all of the above a lot of people feel deeply crappy most of the time and their only fleeting relief comes from snaffling hyper-palatable processed foods, which give them just a few moments at ‘bliss point’ before the cravings for more kick in.
Is it any wonder we have an obesity crisis?
No, it isn’t.
I’ve never been obese but I’ve been addicted to carby foods for sure. You feel like you’re going crazy. Sometimes you just can’t stop eating. You don’t want to, you desperately want to lose weight. You know that eating those foods is making you fatter, but you can’t stop. You feel hungry sometimes even when your belly feels stuffed.
You have crazy arguments in your head as your try to justify why you “need” that food, right now, even though you’d resolved to “be good”. You feel totally out of control, you feel tired, you feel angry at yourself and the world, at times you might also be obsessed with food.
This what I’m referring to when I talk about the link with mental health.
But there is a way out. Many of us just need to open our minds a little and accept that maybe missing a meal at a time when we’re already overfed isn’t going to harm us. Experiencing a bit of hunger is a natural part of the human experience and nothing to be afraid of. We don’t need sugary or carby foods for energy when our fat cells are already stuffed with fuel.
If we can break out of our programming enough just to give a different approach a try we can break out of what seems an impossible maze.
It takes a period of adjustment to adapt to intermittent fasting combined with healthier eating, but when we do those fleeting bliss-point moments can be replaced by sustained naturally high energy levels, the mental fog clears, we enter a more productive state, we re-connect with our bodies and we feel happier, calmer and healthier in body and mind.
Sounds good?
In next post I’ll give more detailed advice on how to get started.
In the meantime, if you want to gear your body up to get the best benefits of fasting, come workout with me!