Fasting after 60 changes more than waistlines, exposing a trade-off many dieters never see coming

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Fasting after 60 changes more than waistlines, exposing a trade-off many dieters never see coming

Fasting at sixty is a different conversation with your body than fasting at thirty ever was

Intermittent fasting affects body weight, metabolism, and cardiovascular health differently across the lifespan, highlighting the need for age-aware approaches. Credit: generated by the author for illustrative purposes

Most folks know intermittent fasting helps with weight loss, usually by limiting your daily eating window or cutting calories a couple of times a week. But does your age change how well this works for you—and might there be some hidden dangers?

Intermittent fasting, such as time-restricted eating or the 5:2 diet, is very popular. With this eating method, you will consume your food within an eight-hour period and fast the rest. With the 5:2 diet, you eat normally five days of the week and drastically cut your calories on the other two days. Many studies show that these techniques are effective, but whether the effectiveness is distributed equally across the population, and especially among people of different ages, is unknown.

A recent comprehensive analysis of 28 clinical trials involving over 1,800 adults shows that intermittent fasting (IF) cuts down body weight and BMI, irrespective of age and sex. However, this deep dive into the data uncovers a surprising truth: the metabolic journey on IF is far from uniform.

A 20-something experiences a distinctly different set of physiological adaptations from those of a 60-year-old. This age-dependent response challenges the traditional one-size-fits-all approach to fasting, revealing that while weight loss is universal, the underlying health impacts are profoundly influenced by where you are in life.

When fat loss comes at the price of muscle

Health isn’t just about the number on the scale. Alarmingly, the study, published in the journal Nutrients, found that in many groups a large share of pounds lost was lean mass, not just fat.

In fact, weight loss often carries a known penalty: typically, 20–30% of the dropped weight is muscle. One fasting trial reported 65% of the weight loss came from lean tissue. Without careful planning, those who fast can end up thinner and weaker. That might be especially dangerous for older adults, who naturally lose muscle each year.

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#2

Umm……no, it doesn’t.

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#3

It depends on the details. My approach of alternate day fasting allows binges (to some extent) and then fasts to lead to weight loss and sufficient resistance exercise (etc) maintains muscle mass.

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#4

I think there are several studies that show IF is good for weight loss.

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#5

IF, which should be referred to as time restricted eating, as fasting implies a prolonged period without food, has not been shown to result in significant weight loss when compared to a normal diet of equal caloric intake.

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#6

Nuff sed. Mitophagy is another issue.

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Equal caloric intake.

Well sure, at some point it is calories in and calories out.

So unless IF causes changes in calories out through metabolic effects, there will be no weight loss. I suspect that IF causes the body to be slightly more efficient as it can shut down the gut for a few extra hours so it actually reduces calories out.

Mind you I said “at some point” because humans are not living in controlled circumstances. The fact is that for a majority of people, they consume less calories during IF.

The easiest way to increase calories out is eat boluses of protein 6 times a day which is the opposite of IF. So the best way to lose weight, keeping “calories in” equal is the opposite of IF.

Like it or not, IF has become so common that “fasting” to most of US society at least is TRE. Best to use duration of a fast if you means 3 days fast or 5 day. The fact is religions have been doing all types of fasts for millennia so it is best to be very specific.

When someone says TRE is not fasting, they are trying to redefine a word that has been around for a long time. Good luck with that. Call it autophagy fast or something.

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#8

There is an issue with IF which results from an amino acid deficit. That is why I limit my fasts to a day (ends up as 36 hours plus).

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#9

The bodybuilders do a lot of things wrong from a longevity standpoint, but they do know how to minimize body fat. Their strategy is typically caloric restriction with adequate protein while continuing to train during this “cutting” period. Water only fasts or restricted protein are thought to lead to a loss of muscle mass especially if the training stimulus is removed. We are interested in longevity and autophagy which require an absence of leucine to bring down mtorc1. So a longevity fast has a different goal than a fat loss fast. Otoh, carrying a lot of fat around, especially visceral fat, is not good for longevity.

#10

Fasting terminology is confusing. I always thought that fasting implies not eating for at least 24 hours.

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#11

Breakfast is the process of breaking the overnight fast.

#12

It’s really a matter of terminology. Some people call the overnight period without food “fasting,” but in my view that’s just a normal circadian rhythm — we sleep at night, and naturally we don’t eat while sleeping. The term “overnight fasting” is mostly used for convenience in medicine, like when a 12‑hour fast is required for a blood draw. That’s not the same thing as intentional fasting for 24–48 hours. I don’t fast, other than not eating while I sleep, and my weight has been stable for over 40 years. If I were to start true intentional fasting, I would expect to lose weight — possibly quite a bit, but I don’t have a reason to do that (113-115 lbs and not moving in any direction).

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#13

The dictionary just says a period of time with deprivation of sometype of food or drink.

Lent is a fast which only excludes certain things.

There is nothing really specific. Like 12 hours or whatever.