We are living longer. Not only that, there is a massive scientific push in the field of longevity to live to 150 years old. And that’s just the beginning.

I’m not here to discuss the pros and cons of living to the ripe old age of 150 (I, for one, have no interest in living that long), but there is very good reason to listen to HOW we could reach that age. That is because the ramifications can have a very positive impact on other diseases that are literally “taking us down” as we age (often referred to as “diseases of aging”) – cancer, heart disease, Alzheimers and type 2 diabetes to name a few.

Regardless of how long we can prolong our livelihoods on this planet, the key is to be healthy for the ride.

Lifespan vs healthspan

Lifespan is the total number of years we live (longevity) whereas healthspan is how many years we remain healthy and free from disease. They are inextricably linked.

Both are affected by a myriad of factors, often falling under the umbrellas of emotional factors (loneliness, emotional stress, personality, outlook on life, etc), and/or biological factors. My focus here is from the biological perspective – think genes and DNA, specifically when it comes to food (exercise also plays a big role, but that’s for a future newsletter).

David Sinclair, author of the book Lifespan: Why We Age and Why We Don’t Have To, is a professor in the Department of Genetics and the co-director of the Paul Glenn Center for Biology of Aging Research at Harvard Medical School. He is best known for his work on understanding why we age and how to slow its effects.

David’s overall recommendation would be this:

The key to longevity when it comes to food is to eat less often.

(Note - when I use the word longevity, I am also talking about healthspan – how we can stay healthy as we age. The recommendations for longevity are the same as they are for staying healthy during that time).

Eating less often

This is not about eating fewer calories (although it could mean that), nor is it about calorie deprivation. It’s more about eating calories within a shorter period of time.

And it is the period of not eating that is the focus here, because that period of “hunger” is critical to boosting the body’s defences against aging, and in turn maximizing health and longevity.

Hormesis

So how is being hungry a good thing?

Eating less often triggers longevity genes in our body, and it does this by stressing our system - known as hormesis.

In the field of biology and medicine, hormesis is defined as "an adaptive response of cells or organisms to moderate (usually intermittent) stress." (1)

Or, more blatantly, what doesn’t kill you makes you stronger. That is, in effect, what exercise is all about – breaking down muscle in order to build it back up again, even stronger.

But in this case we are talking about food – or lack thereof. By stressing the body through taking longer breaks between eating times, we can activate our longevity genes - critical for helping us age well.

Longevity Genes

There are three classes of longevity genes, each triggered by external stimuli/stressors. I will give a brief overview of each, but feel free to jump to the bottom of this newsletter for recommendations if your eyes start to glaze over ;-)

1. Sirtuins – a sirtuins role is to extend lifespan (and support healthspan) by protecting our DNA and making sure that genes stay turned on when they are supposed to be on (trust me, this is very important).

Sirtuins are activated by low energy - specifically lower glucose levels. When we don’t eat we have lower glucose levels.

(Note that we evolved this way - the hunter-gatherers were not running to the fridge every time they got hungry. Getting food was a serious undertaking.)

2. AMPK – AMPK stimulates the body to make more mitochondria, which are the power plants of every cell and create energy for all of our biological processes. Hence AMPK is critical for longevity, especially since we lose mitochondria as we age.

AMPK, like sirtuins, is activated by low energy – when we are hungry, we make more of it.

3. mTOR – mTOR activates autophagy. Autophagy is a process of removing damaged parts of cells and recycling others – like cellular housekeeping.

In the case of mTOR, it recycles old proteins (a good thing). The twist is that mTOR is activated by amino acids (protein), and yet we don’t want mTOR to be activated. By downregulating the activity of mTOR, we get the benefits of autophagy. Aka, eating less protein.

So… what is the best way to activate these genes when it comes to food?

Basically, some sort of fasting.

But for the purpose of this newsletter, I only want to focus on Time-Restricted Feeding (TRF - often referred to as Intermittent Fasting). For more details on different types of fasting, refer to one of my earlier blogs titled, Why intermittent fasting is all the rage.

With respect to time-restricted feeding, there are varying eating windows, with 12/12 and 16/8 being the most common - the first number reflects the hours you aren’t eating, and second reflects the eating window where you are eating.

For example, a 12/12 would be if you finished eating dinner at 8pm in the evening, and started your breakfast at 8am the next morning.

Is there a TRF window that is considered "the best" for longevity?

Yes. Studies have shown that in order to most effectively trigger the sirtuin and AMPK pathways, you want to have at least 16 hours of not eating (if not longer). That would mean if you stopped eating at 8pm in the evening, you wouldn’t eat until 12noon the following day. It would take your body a couple of weeks to adapt to this in order to overcome the feeling of hunger during the time of non-eating (where you normally would be satiated).

The secret? Liquids – lots of water and herbal teas. And if there are days where hunger pangs are too much to handle, the best option is to have a handful of nuts (the fat in nuts doesn't affect your blood sugar).

The shorter the eating window, the more effective it is for longevity, states David Sinclair. For example, only having one meal a day, as he does, would essentially be a two hour window of eating and a 22 hour window of fasting.

For me, given food is one of my biggest pleasures in life, this option is definitely not on my list, no matter how many years it may add to my life!

On that note, it is very important to understand that I’m not actually recommending any type of fasting. Not only am I not allowed to do so in this forum, but more importantly, we are all individuals. We have different lifestyles, different tolerances, different sexes, different microbiomes, different health histories… the list goes on. Diets and ways of eating affect everyone in different ways. There is no one "right" way.

Rather, my goal (always) is to provide information and for you to make your own choices.

There are definitely benefits associated with time restricted feeding (TRF), even if doing the minimum 12 hours eating and 12 hours fasting (which is recommended in general, as it gives your digestive system a break and depletes your glycogen (glucose) stores before loading up on them again). Benefits include:

Lower blood sugar levels
Improved blood pressure
Improved heart function
Weight loss, especially stubborn belly fat
Increased cognition (reduced brain fog)
Enhanced aerobic capacity

As an aside, it’s no wonder that Intermittent Fasting (TRF) is the most popular “diet” right now in the US. It’s inexpensive, accessible to everyone and can have a big impact on our health, healthspan and longevity.

What about cutting back on protein?

In order to trigger (or not trigger in this case) mTOR, the other longevity gene, it is suggested that we avoid/cut back on super high proteins – think meat. Otherwise, the autophagy, in this case the recycling of protein that low mTOR stimulates, won’t be initiated.

Nowadays, the concept of cutting back on meat isn’t too much of a surprise… the focus of both the Blue Zones and the Mediterranean diet. We know that amino acids (the building blocks of protein) are essential, but taking the proper steps, we can get all the protein we need from diets such as the Med diet, or with a vegetarian or vegan approach. It just takes work to ensure our protein (and other nutritional needs) are covered.

Legumes, nuts, soy and quinoa are all good sources, plus all plants have a certain amount of protein. Finally, certain combinations of foods (ie - rice and beans together) provide a full amino acid complement. These Blue Zone recipes provide great suggestions if you want to go down that path.

Are there certain types of foods we should be concentrating on wrt to longevity and healthspan?

For sure - the same foods I talk about all the time - eat more vegetables, berries, legumes, whole grains, nuts, olive oil, good fats (and a splash of red wine of course ;-). And minimize sugar and processed foods. As for meat... there is much research being done on how plant based diets enhance longevity (compared to other approaches), but as always it's a personal choice.

Summary

I've thrown a lot of information at you. But in fact, the key elements to remember with respect to longevity and healthspan are pretty straightforward:

Eat less often* – for best effects, skip one meal a day, either breakfast or dinner. Think of hormesis - how stressing the body (within limits) strengthens it in the long term. It puts our body into a state of "want" in order to fight diseases of aging, such as cancer, Alzheimers, heart disease and T2D, to achieve ultimate health in old age and enhance longevity
- drink lots of liquids (water and herbal teas) to reduce feelings of hunger
Try to avoid snacking - have a handful of nuts if necessary
Reduce meat intake

*NOTE: it’s always best to work with a professional when doing any sort of fasting. Plus it is not recommended if you are pregnant, suffer from disordered eating or having any adrenal/thyroid issues.

Remember – the average lifespan is getting longer, but not necessarily better. We want to ensure those extra years are as productive as possible. In order to do this, we need our health. So let’s start thinking in terms of BOTH healthspan and lifespan.

Thanks for reading :)

Gillian xx
PS - for those of you in Toronto and surrounding area, my Walk & Talk Wellness Reset is up and running. It's a fantastic way to get the therapeutic benefits of a walk in nature while getting personalized nutritional and lifestyle recommendations. Let me help you set some goals - nutrition, sleep, cognitive health, stress management or movement - and put some systems in place to help take you to the next level. You can reach me by replying to this email or at gbwellness.ca.

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