Caffeine, Energy Expenditure, and Aging

In the context of a ketogenic diet, modest calorie restriction, and regular exercise, I have been considering re-introducing caffeine into my daily routine. I removed it months ago because there is substantial evidence that it induces a kind of transient insulin resistance (discussed in this article) – something I didn’t want when I was consuming substantial daily carbs. I also briefly discuss my hypothesis of energy production failure as a primary cause of aging degeneration, and support that with (very few) references (for now)…….


Over the past ~1 year, I have started to consider a new-to-me interpretation of the aging science literature: that much of the degeneration in aging is caused by a systemic decline in energy production and utilization. I am currently working on a more detailed, written analysis of this topic for Long Life Labs’ Original Research.

Related to this, I have been consistently consuming a ketogenic diet for approximately 2 months (Starting Sept. 1, 2014). I have confirmed my state of ketosis by both urinalysis ketone strips and blood ketone testing. Some of the scientific literature about a ketogenic diet suggests that, especially for the brain, a ketogenic diet helps energy production and utilization, thereby enabling cells to stay alive longer and healthier than they otherwise would (e.g. one study reviewing a ketogenic diet, ketones, and Alzheimer’s by Henderson, 2008).

In an effort to improve my lipid panel (esp. lower my LDL), I have been consistently trying to become leaner (I’m currently around 10% body fat – this is my educated guess, and haven’t measured it with the proper tools). To achieve this, over the past ~6 years, I have tried many different diets, exercise routines, exercise types, and supplements. My % body fat seems to have stayed pretty much the same. It turns out that a ketogenic diet alone may lower LDL, regardless of changes in body fat % — we’ll see in December, when I’ll get my 90-day ketogenic diet blood panel done.

I understand that to achieve lower body fat, one must have fairly low insulin, which enables greater fat oxidation (“fat burning”), or using body fat as energy. To have lower insulin, one must have lower blood glucose. This suggests that one must become very insulin sensitive, which can be accomplished with, among other things, high-intensity exercise.


Prior to adopting a ketogenic diet, I was trying to lower my body fat with a moderate volume of strength training, high-intensity interval training, and a higher-carb diet. I was also drinking caffeine at the time. I did not get results I was satisfied with (actually, I didn’t see much change at all; my body fat stayed approximately the same, although my fitness – i.e. strength, running speed, and endurance – was improving).

This was about the time I read that caffeine apparently induces a kind of transient insulin resistance. In several studies I found, it turned out that caffeine causes glucose and insulin to be higher than they otherwise would be without caffeine (see references here and here). Of course, I was concerned about this, because as I just explained, I wanted glucose and insulin to be lower. So I quit consuming caffeine.

Fast-forward a few months to today, and I’m actually seeing progress in fat loss progress on a ketogenic diet, without caffeine. At the beginning, I weight 181 lbs. I now weigh 168 lbs. Visually, I look leaner, and I feel well. My cardiac fitness has improved as well (I’m currently training to achieve a < 6-minute mile, and am making consistent progress). My body temperature has even stayed fairly normal (as opposed to much lower body temps I experienced on a higher-carb diet).

Some people complain about not having energy on a ketogenic diet, and that hasn’t been my experience. If anything, I feel better and more energetic in a ketogenic diet – which sounds like it conflicts with what I’m about to say: I have occasionally felt sluggish on a ketogenic diet. However, I also have a tendency to under-eat. This sluggishness correlates with times when I’m under-eating substantially, and it is fixed with increased food intake. However, given that I’m both (probably) well-adjusted to a ketogenic diet (via 2 months of consistent ketosis, with substantial exercise throughout), and I’m fairly athletic, something that’s been bothering me is: why can I not tap into my body fat better than I am?

Fat utilization and adrenaline

One important aspect of using body fat for energy is adrenaline (a.k.a. “epinephrine”) signaling (a.k.a. “sympathetic nervous system“). After doing some non-scientific thinking on this topic, I suspect that my life is very comfortable – i.e. very low stress, i.e. very low in adrenaline and stress hormones. I love this. It’s great. After cultivating a healthy perspective over the past ~5 years, as well as adopting a ketogenic diet (which I suspect is less of a stress-hormone-roller-coaster than a high-carb diet), I feel very relaxed. I am not easily upset, nervous, or anxious. I’m healthy, level-headed, and focused.

How relaxed is “too relaxed”? 

But I wonder: could this very relaxed lifestyle, with its associated low adrenaline signaling, keep me from accessing my body fat as energy? For example: I notice that my energy level improves when I exercise, which is known to increase adrenaline signaling. What if I could, to some extent, control the amount of adrenaline, and thereby my energy level, mood, and level of productivity? Well, people already do that by drinking coffee and tea, and this is why I’m considering (re)implementing daily caffeine intake.

I don’t have many adrenaline-inducing activities in my life, besides exercise.

It’s an interesting situation: in a relaxed environment that engenders relaxation and complacency, I’m considering essentially, gently “supplementing” with stress (hormones, via caffeine intake), to boost energy and productivity even higher.

Let me clarify: I’m not saying I’m considering “jacking up” on stress hormones for the purpose of getting leaner. Well, ok – to a small extent, that’s kind of what I’m considering. But I’m actually considering a targeted, moderate adrenaline-boost (via caffeine intake) for the purpose of health and longevity. Nothing extreme. Come to think of it, my current lifestyle may be a bit of an evolutionary aberration: I do not worry about predators, starvation, harvests, drought, hunting, fights, tribal battles, or approval-seeking from potential mates (for children). In this context, a small “adrenaline supplement” – timed well to minimize sleep disruption – does not seem unreasonable.

Energy production and aging

If I’m correct that caffeine (and its associated increase in adrenaline signaling) enhances energy production and utilization, and that much of the degeneration in aging is caused by declining energy production, then a ketogenic diet (which apparently enhances energy production) combined with caffeine intake (which apparently enhances energy expenditure) may be very good for health and longevity.

I wonder if the studies that found an association between increased caffeine intake and lowered incidence of Alzheimer’s Disease supports my hypothesis (Alzheimer’s is considered by some researchers to be a kind of failure of energy production in the brain, which is why it is sometimes called “Type 3 diabetes”). This is further corroborated by studies considering a ketogenic diet for improvement in Alzheimer’s (this is ‘corroborating’ because both caffeine intake, and a ketogenic diet, enhance fat metabolism, basically and theoretically enabling your brain to better use fat for its energy needs).

If you consider this for yourself, please keep in mind that my situation (lean, male, athletic, no health problems, ketogenic diet, 100-200 mg caffeine/day (1-2 cups of coffee/day), “slow caffeine metabolizer” as reported to me by 23andme, very insulin sensitive/glucose tolerant) may be very different than yours. Plan accordingly.

Caffeine and energy expenditure

Related to this (and because of this, I’m strongly leaning toward going back to daily caffeine intake), I recently read a study which found caffeine to apparently increase energy expenditure by ~13%. I first wrote about this in early Oct (2014). This study also found oxidative fatty acid disposal (i.e. “fat burning”) to be increased by 44%. Given that I’m on a ketogenic diet, this may be very good for body fat utilization.

Here are a few more references for a relationship between caffeine intake and energy expenditure:

Caffeine and mood

Then there are the studies (which I’ve read multiple times) of how both acute, and chronic caffeine intake improves mood (could it be the improved energy expenditure?).

Some references on caffeine and mood:

Sounds like I need to buy some caffeinated coffee – or make some tea.

…..Tomorrow morning.

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Maximus Peto is a longevity scientist focused on the biology of aging, health, nutrition, exercise, lifestyle, and longevity. In his scientific research, he has scanned 160,000+ scientific articles, read 8,000+ scientific abstracts, and studied 1,500+ full-text scientific publications. Maximus has worked with several leading organizations in aging and longevity, including the SENS Research Foundation, the Methuselah Foundation, and the Life Extension Foundation. He shares his knowledge of keeping people alive and healthy at Long Life Labs.