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!

Washing Our Hands Of It

In Tuesdays’s newsletter, we asked you how often you wash your hands, and got the above-depicted, below-described, set of self-reported answers:

• About 54% said “More times per day than [the other options]”
• About 38% said “Whenever using the bathroom or kitchen
• About 5% said “Once or twice per day”
• Two (2) said “Only when visibly dirty”
• Two (2) said “I prefer to just use sanitizer gel”

What does the science have to say about this?

People lie about their handwashing habits: True or False?

True and False (since some people lie and some don’t), but there’s science to this too. Here’s a great study from 2021 that used various levels of confidentiality in questioning (i.e., there were ways of asking that made it either obvious or impossible to know who answered how), and found…

❝We analysed data of 1434 participants. In the direct questioning group 94.5% of the participants claimed to practice proper hand hygiene; in the indirect questioning group a significantly lower estimate of only 78.1% was observed.❞

~ Dr. Laura Mieth et al.

Source: Do they really wash their hands? Prevalence estimates for personal hygiene behaviour during the COVID-19 pandemic based on indirect questions

Note: the abstract alone doesn’t make it clear how the anonymization worked (it is explained later in the paper), and it was noted as a limitation of the study that the participants may not have understood how it works well enough to have confidence in it, meaning that the 78.1% is probably also inflated, just not as much as the 94.5% in the direct questioning group.

Here’s a pop-science article that cites a collection of studies, finding such things as for example…

❝With the use of wireless devices to record how many people entered the restroom and used the pumps of the soap dispensers, researchers were able to collect data on almost 200,000 restroom trips over a three-month period.

The found that only 31% of men and 65% of women washed their hands with soap.❞

Source: Study: Men Wash Their Hands Much Less Often Than Women (And People Lie About Washing Their Hands)

Sanitizer gel does the job of washing one’s hands with soap: True or False?

False, though it’s still not a bad option for when soap and water aren’t available or practical. Here’s an educational article about the science of why this is so:

UCI Health | Soap vs. Hand Sanitizer

There’s also some consideration of lab results vs real-world results, because while in principle the alcohol gel is very good at killing most bacteria / inactivating most viruses, it can take up to 4 minutes of alcohol gel contact to do so, as in this study with flu viruses:

Situations Leading to Reduced Effectiveness of Current Hand Hygiene against Infectious Mucus from Influenza Virus-Infected Patients

In contrast, 20 seconds of handwashing with soap will generally do the job.

Antibacterial soap is better than other soap: True or False?

False, because the main way that soap protects us is not in its antibacterial properties (although it does also destroy the surface membrane of many bacteria and for that matter viruses too, killing/inactivating them, respectively), but rather in how it causes pathogens to simply slide off during washing.

Here’s a study that found that handwashing with soap reduced disease incidence by 50–53%, and…

❝Incidence of disease did not differ significantly between households given plain soap compared with those given antibacterial soap.❞

~ Dr. Stephen Luby et al.

Read more: Effect of handwashing on child health: a randomised controlled trial

Want to wash your hands more than you do?

There have been many studies into motivating people to wash their hands more (often with education and/or disgust-based shaming), but an effective method you can use for yourself at home is to simply buy more luxurious hand soap, and generally do what you can to make handwashing a more pleasant experience (taking a moment to let the water run warm is another good thing to do if that’s more comfortable for you).

Take care!