Introducing Fasting, Calorie Restriction and Longevity


I’m constantly entertained by half-starved fitness gurus enthusiastically selling their latest and greatest fad diets.

Some are vegan, others are carnivores. Add keto, raw, OMAD fans and extreme cleansing to this list, and it is no wonder people are wary.

Yet, clinical data – pioneered by Dr Valter Longo – overwhelmingly shows fasting has massive benefits for healthy longevity and leads to a lower incidence of killer diseases.

Key to fasting benefits is cellular rejuvenation.

Fasting benefits are easy to reach with simple habits. Long fasts may be dangerous. They require medical supervision. Short (daily) fasts, time restricted eating and fast-mimicking diets all get you the core benefits without the pain of being constantly hungry.

Add deliberate choices of what you eat, and fasting benefits multiply.

This page introduces the key ideas linking fasting and calorie restriction to longevity. It shows you how simple habits and smarter food choices work together for a healthier life.

Fasting and Healthy Aging: Avoiding Hunger with Habits, Not Willpower

You don’t need willpower to fight through constant hunger pangs to fast. In fact, with the right habits systemising what and when you eat becomes a pleasure.

This page starts with the science of fasting. It introduces the different types of fast, and the outsized benefits you get from small changes.

The first steps to developing healthy eating habits can be as small as changing the order of eating the food on your plate. Or swapping a sugary snack for something just as enjoyable but not so carb-rich.

Once you feel the benefits, you’ll be keen to take the next steps.

That is where longevity habits come into play. Simple, effective steps which quickly snowball – providing a health boost now, plus a longer, less frail lifespan later.

How Fasting Improves Your Healthy Lifespan

Before I get to the types of fast, here is a quick-fire overview of how fasting helps.

The types of food you eat when not fasting are critical. Anyone that fasts, only to binge on carbs, sugars and processed foods are only fooling themselves. Benefiting from fasting involves a healthy, balanced diet that keeps within sensible calorie guidelines.

Benefits accrue as you go longer without food.

Here are the mechanisms by which fasting improves your lifespan:

  • Autophagy: This is the reuse of cellular components. The body breaks down older, less effective cells, and creates new, rejuvenated ones as a response to fasting.
  • Improved Insulin Sensitivity: Getting off the ‘Glucose Rollercoaster’ of sugar highs and crashes avoids Insulin resistance, which leads to weight gain and (eventually) type II diabetes.
  • Reduction in Stored Fat: White fat cells cause chronic inflammation. This is causally linked to the diseases that kill people, atherosclerosis, cancer, Alzheimer’s and more.
  • Microbiome Boosts: A healthy gut microbiome is vital to overall wellbeing. An out of balance one has knock-on effects including inflammation and impaired immune response.
  • Improved Sleep: Getting a solid night of rest is more than just a boost to brain health. It directly feeds into cravings, mood and lets you resist those bad habits which can unbalance your cellular signalling in multiple ways.

Fasting and Chronic Diseases

The body of clinical data supporting fasting is huge.

Examining the research, you will quickly find improvements in cardiovascular health, incidence of cancer, improvements in type 2 diabetics and even some improvements in the results of chemotherapy.

As always with medical benefits, I defer to the scientists and medical professionals. Here are a selection of papers and meta-analysis:

  • Add these before go-live
  • Two
  • Three

Fasting and Longevity: The Different Types of Fast

Ask about fasting and you get drowned under a tsunami of acronyms.

IF, CR, OMAD, TRE and more are enough to make the best of us give up and reach for a snack.

This section covers the main types of fast quickly, with links to detailed guides for the full picture.

For anyone new to fasting, a quick win is to limit your food intake to 8 or 10 hours in a day. When you feel the benefits, the more involved types of fasting can be added to your list.

Types of Fast:

  • Time Restricted Eating: Here you choose a period of between 6 and 10 hours and do all your eating then. Skipping breakfast, with lunch and dinner between 12pm and 8pm is the most popular format. I do this one, with a 12pm to 6pm window (and no simple carbs until my evening meal)
  • Intermittent Fasting: While ‘IF’ is frequently used interchangeably with Time Restricted Eating, it refers to longer fasts. They can be between 24 hours and multiple days. This type of fast is done weekly, monthly, or even less frequently. Going too long too soon is dangerous – so make sure you understand the risks.
  • Calorie Restriction: This can involve working with a permanent calory deficit, or phasing. An example of phased calorie restriction is the 5/2 diet. Here you have a deliberate deficit two days per week, eating normally otherwise. Alternate day fasting is another example of phased calorie restriction.
  • One Meal a Day: This is a strict form of Time Restricted Eating. You consume all your food in one giant meal. OMAD takes some practice and will reduce your overall calorie consumption as it is hard to eat too many calories in a single meal.
  • Fast Mimicking Diet: FMD aims to get the benefits of fasting, without going hungry. You can eat foods which don’t trigger an insulin response or provide protein. An example is the ‘Bulletproof’ diet from Dave Asbury. This allows for butter and coconut oil in your morning coffee.

The other axis by which fasting diets work is by food type. Examples are the Keto diet, vegan diet, pescetarian, carnivore, Mediterranean and more. With the timing regimes – multiple combinations of type / time are possible.

Small Steps: Starting a Fasting Longevity Habit with Super-Quick Wins

It is not just when you eat that comes with longevity benefits, you must be conscious of what you do and do not eat too.

When it comes to building habits, there is a piece of low-hanging fruit that is simple and effective.

Don’t eat for at least three hours before you go to bed.

This will improve your sleep dramatically (in quality if not duration). Benefits then cascade into your food and lifestyle choices the next day. With high quality sleep, you are more likely to choose healthy foods, more likely to exercise and less likely to give in to those bad habits.

Each day that goes by without a late-night snack is another step towards a healthier, less frail future.

I dive into longevity habits elsewhere on this site. Here are some quick wins when it comes to building a fasting habit. These are separate from food choices and the exact fasting sequence you pick:

  • Don’t go all-in too soon: Trying full day fasts or strict regimes too soon will backfire. Work your way to a smaller eating window gradually as the benefits accrue.
  • Remove temptation from your cupboards: Willpower is short-term, if you have snacks in your cupboards, it is only a matter of time before you eat them.
  • Prepare healthy snacks in advance: Make it easy to eat healthy by prepping wholesome snacks and healthy meals in advance.
  • Forgive yourself occasional cheats: We all have our moments of weakness, and just like with all my longevity habits, acknowledging them and working with them is my choice. A cheat day, or occasional indulgence will make your regular fasting easier to commit to.

Fasting Benefits for Longevity: Combining Fasting with Smart Nutrition Choices

Combining fasting with smart choices of what you eat will multiply the health benefits.

Regular diets are full of poisons. You’ll find them covered in detail elsewhere here at the Age Well Times. Here is a reminder.

  • Sugar: This is the big killer, damaging cells, triggering fat storage and (eventually) leading to insulin resistance and type 2 diabetes. Sugar is pervasive, toxic, and cutting down is the single best dietary change you can make.
  • Simple Carbs: That humble slice of bread, pasta dish or potato are rapidly turned into glucose on digestion. Think of them as sugar, which hits your bloodstream faster if it is finely ground. A ‘carb crash’ is a sugar crash.
  • Processed Foods: Ready meals often have a long list of chemical additives. They also contain high levels of sugar and salt. Smoked meats or burned food (think barbeques) trigger inflammation. Fresh food, which was not mass produced in a factory should be your default.
  • Booze: I want wine to be safe, you want gin, or beer to have some benefits. Sorry, this is simply not the case. Alcohol ruins sleep, it disrupts our gut microbiome and (often) comes with a sugar spike. If you won’t cut it out, at least cut it down.
  • Caffeine: Adenosine is a neurochemical that accumulates through the day. It creates sleep pressure, which together with melatonin, lets us sleep. Caffeine binds to the receptors of Adenosine, stopping this process. Keep your coffee to the mornings as a default.

Instead, eat a balanced diet with leafy greens, organic meat (or alternative clean protein source), oily fish and legumes. Add olive oil, garlic, and fermented foods – and keep those simple carbs to a minimum.

Wrapping Up: Getting into the Fasting Habit Will Boost Your Healthy Lifespan

Fasting will boost your healthy lifespan. And getting the benefits without those gnawing pangs of hunger is easy.

Combining fasting with smart choices of what you eat multiply the benefits.

It took me 18 months to get to a comfortable (and carb-lite) 18/6 routine. I still allow myself the occasional indulgence, and still have work to do on longer (day+) fasts.

Along with sleep and exercise, fasting is a key habit. When you are ready to dive in to understanding how food, fasting and longevity interact – the detailed guides listed below are the next steps.




Mark’s Blog





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