Caloric Restriction with Optimal Nutrition

Yesterday, we asked you “What is your opinion of caloric restriction as a health practice?” and got the above-depicted, below-described spread of responses:

• 48% said “It is a robust, scientifically proven way to live longer and healthier”
• 23% said “It may help us to live longer, but at the cost of enjoying it fully”
• 17% said “It’s a dangerous fad that makes people weak, tired, sick, and unhealthy”
• 12% said “Counting calories is irrelevant to good health; the body compensates”

So… What does the science say?

A note on terms, first

“Caloric restriction” (henceforth: CR), as a term, sees scientific use to mean anything from a 25% reduction to a 50% reduction, compared to metabolic base rate.

This can also be expressed the other way around, “dropping to 60% of the metabolic base rate” (i.e., a 40% reduction).

Here we don’t have the space to go into much depth, so our policy will be: if research papers consider it CR, then so will we.

A quick spoiler, first

The above statements about CR are all to at least some degree True in one way or another.

However, there are very important distinctions, so let’s press on…

CR is a robust, scientifically proven way to live longer and healthier: True or False?

True! This has been well-studied and well-documented. There’s more science for this than we could possibly list here, but here’s a good starting point:

❝Calorie restriction (CR), a nutritional intervention of reduced energy intake but with adequate nutrition, has been shown to extend healthspan and lifespan in rodent and primate models.

Accumulating data from observational and randomized clinical trials indicate that CR in humans results in some of the same metabolic and molecular adaptations that have been shown to improve health and retard the accumulation of molecular damage in animal models of longevity.

In particular, moderate CR in humans ameliorates multiple metabolic and hormonal factors that are implicated in the pathogenesis of type 2 diabetes, cardiovascular diseases, and cancer, the leading causes of morbidity, disability and mortality❞

Source: Ageing Research Reviews | Calorie restriction in humans: an update

See also: Caloric restriction in humans reveals immunometabolic regulators of health span

We could devote a whole article (or a whole book, really) to this, but the super-short version is that it lowers the metabolic “tax” on the body and allows the body to function better for longer.

CR may help us to live longer, but at the cost of enjoying it fully: True or False?

True or False, contingently, depending on what’s important to you. And that depends on psychology as much as physiology, but it’s worth noting that there is often a selection bias in the research papers; people ill-suited to CR drop out of the studies and are not counted in the final data.

Also, relevant for a lot of our readers, most (human-based) studies recruit people over 18 and under 60. So while it is reasonable to assume the same benefits will be carried over that age, there is not nearly as much data for it.

Studies into CR and Health-Related Quality of Life (HRQoL) have been promising, and/but have caveats:

❝In non-obese adults, CR had some positive effects and no negative effects on HRQoL.❞

Source: Effect of Calorie Restriction on Mood, Quality of Life, Sleep, and Sexual Function in Healthy Non-obese Adults

❝We do not know what degree of CR is needed to achieve improvements in HRQoL, but we do know it requires an extraordinary amount of support.

Therefore, the incentive to offer this intervention to a low-risk, normal or overweight individual is lacking and likely not sustainable in practice.❞

Source: Caloric restriction improves health-related quality of life in healthy normal weight and overweight individuals

CR a dangerous fad that makes people weak, tired, sick, and unhealthy: True or False?

True if it is undertaken improperly, and/or without sufficient support. Many people will try CR and forget that the idea is to reduce metabolic load while still getting good nutrition, and focus solely on the calorie-counting.

So for example, if a person “saves” their calories for the day to have a night out in a bar where they drink their calories as alcohol, then this is going to be abysmal for their health.

That’s an extreme example, but lesser versions are seen a lot. If you save your calories for a pizza instead of a night of alcoholic drinks, then it’s not quite so woeful, but for example the nutrition-to-calorie ratio of pizza is typically not great. Multiply that by doing it as often as not, and yes, someone’s health is going to be in ruins quite soon.

Counting calories is irrelevant to good health; the body compensates: True or False?

True if by “good health” you mean weight loss—which is rarely, if ever, what we mean by “good health” here at 10almonds (unless we clarify such), but it’s a very common association and indeed, for some people it’s a health goal. You cannot sustainably and healthily lose weight by CR alone, especially if you’re not getting optimal nutrition.

Your body will notice that you are starving, and try to save you by storing as much fat as it can, amongst other measures that will similarly backfire (cortisol running high, energy running low, etc).

For short term weight loss though, yes, it’ll work. At a cost. That we don’t recommend.

❝By itself, decreasing calorie intake will have a limited short-term influence.❞

Source: Reducing Calorie Intake May Not Help You Lose Body Weight

See also…

❝Caloric restriction is a commonly recommended weight-loss method, yet it may result in short-term weight loss and subsequent weight regain, known as “weight cycling”, which has recently been shown to be associated with both poor sleep and worse cardiovascular health❞

Source: Dieting Behavior Characterized by Caloric Restriction

In summary…

Caloric restriction is a well-studied area of health science. We know:

• Practised well, it can extend not only lifespan, but also healthspan
• Practised well, it can improve mood, energy, sexual function, and the other things people fear losing
• Practised badly, it can be ruinous to the health—it is critical to practise caloric restriction with optimal nutrition.
• Practised badly, it can lead to unhealthy weight loss and weight regain

One final note…

If you’ve tried CR and hated it, and you practised it well (e.g., with optimal nutrition), then we recommend just not doing it.

You could also try intermittent fasting instead, for similar potential benefits. If that doesn’t work out either, then don’t do that either!

Sometimes, we’re just weird. It can often be because of a genetic or epigenetic quirk. There are usually workarounds, and/but not everything that’s right for most people will be right for all of us.

Take care!