Drinking strong coffee before exercising increases fat-burning, new study finds

> Subjects ingested 3 mg/kg of caffeine or a placebo at 8am and 5pm

3mg/kg is over 250mg of caffeine for an average weight man. Twice a day makes that 500mg.

An 8.4oz can of Red Bull contains 80mg of caffeine. They were giving these people an amount of caffeine equivalent to 6 cans of Red Bull. Not a perfect comparison because Red Bull contains other ingredients, but that's still a lot of caffeine. For another point of reference, that's 2.5 shots of 5 hour energy (200mg caffeine per bottle).

To top it off, the subjects were caffeine-naive, so they had no caffeine tolerance. They must have been feeling extremely energetic.

No wonder they burned more fat. I'm not sure this is going to translate to your casual coffee drinker or someone with a high caffeine tolerance.

Yet another question is, whether or is even healthy. It might just be that not burning that fat more quickly can be healthier then drinking so much coffein.

3mg/kg for an average weight man is about 3 cups of coffee.

Interestingly I've heard about a strong relationship between heart attacks and consumption of energy drinks like Monster/Red-Bull.

I used to drink a lot of Red Bull and stopped as a result. But I sometimes think one of the reasons I haven't put on weight despite my lifestyle is because of my caffeine habits.

I am pretty sure that not sleeping at all also increases fat burning as body uses less energy when asleep

The fat burning might be from reaction of organism that is not used to a lot of daily caffeine ingestion. For example, when I don't use caffeine for a long time my heart rate increases when I increase amount of coffee I drink. But then goes back after some time (presumably when my body gets accustomed to it again).

Also, this kind of research must be read with a little bit of scientific background.

It is easy to get an impression author wanted to establish causation, but in reality this research only shows correlation, and correlation does not prove causation.

Yeah one can is my limit (let's say, for a 4h period). I can't imagine what would feel taking the equivalent of taking that amount all at once. Probably the usual effects (headache and severe dizziness)

That being said, caffeine is a good pre-workout.

Seems like a lot when put in terms of Redbull, but isn't really in the context of athletes and performance. 5mg/kg is a common number as a pre-event dose for endurance athletes, and science seems to be mixed on ideal due to large individual variation in tolerance, response, and metabolics[1]. There are many 'thermogenic' fat loss supplements that have 150mg+ per dose taken multiple times a day.

Cyclists I know commonly take 400mg before a race to training session, and often top up over the course of the event if it's more than a couple hours. So I don't think the numbers reported are high, unless casual coffee is your basis comparison. But in the context of caffeine for fat loss, where supplements have high amounts, the numbers seem in line with common use.

1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5752738/

240mg is pretty common for the canned energy drinks

Extrapolating from your comment, I guess we'd kind of want a blocked design that is placebo-vs-caffeine and exercise-vs-none.

That would tell us whether there is just an additive effect of high-dose caffeine and exercise, or if somehow the caffeine is interactive with exercise (i.e., has a bigger effect in the exercise group than in the rest group).

Poor sleep is associated with weight gain.

A tall (smallest size) pyke roast from Starbucks is 235 mg of caffeine. A venti (what I normally get) is 410 mg.

I wonder if that’s because sleepiness is associated with poor impulse control. I know when I’m super tired I tend to eat whatever I want the next day.

> I am pretty sure that not sleeping at all also increases fat burning as body uses less energy when asleep

From the admittedly little I know about biology and sleep science; I thought it was universally accepted that poor sleep harms your metabolism and thus would make fat-burning less likely.

The subjects were caffeine-naive non-athletes. They had zero caffeine tolerance.

500mg is a huge amount for a caffeine-naive person, no matter how you look at it. No one goes from drinking zero caffeine to 6 Red Bulls per day without experiencing abnormally high stimulation.

The smallest size at Starbucks is “short”, it's just not listed on the menu.

A grande (16oz) drip coffee from starbucks is over 300mg of caffeine. The problem with Red Bull is the sugar.

Back in the late 00’s I discovered Redbull really helped me overcome after-lunch food-coma. I’d drink one right after lunch to help me get back to work and focus for the rest of the day.

After about 6 months of this, one day I was sitting at my desk having just finished my afternoon Redbull, and felt my heart skip a beat, literally. Like a little mini-heart attack. Scared the shit out of me, and I quit Redbull cold turkey that day.

At the time I was really into cycling, riding about 100 miles per week (50 on the weekend plus daily bike commute). I was in tip-top shape, with no family history of heart problems, and an otherwise normal, low-sugar, whole food diet.

Never experienced that since, and I wouldn’t be surprised if there are studies that find a link between super-high caffeine energy drinks and heart or other health problems.

I'm not sure you two are disagreeing?

Ah, this is called an ectopic heart-beat (usually harmless). Back when I drank too much coffee and didn't sleep in my last year of college, I got a few of these. Now I'm a one-cup-a-day kind of guy, and it hasn't happened much anymore.

That and you may be having an extra meal whereas you otherwise would have been asleep.

There is that and there is the “enforced fasting interval” that sleep is.

No, it is not "universally accepted".

It is actually opposite. Most organisms under stress increase their energy consumption.

A good proxy for energy consumption by your body is your heart rate. Heart rate is linked to the amount of blood distributed through your body and amount of blood is amount of oxygen that is needed by your cells for metabolism.

And amount of oxygen used by cells is almost equal to the amount of energy produced (excluding those rare anaerobic regimes).

Heart rate is always lowest at night during sleep.

What you probably meant is that a person who has poor sleep will have a statistical tendency to eat more, for many reasons. One it is more difficult to exercise willpower when you are not rested well. It might also be more difficult to accurately judge whether what you feel is hunger.

To accurately compare energy use by body you would have to externally limit amount of calories ingested to same level and figure out how much CO2 you emit or how much weight you lost.

Otherwise you are measuring your regulating machine -- ie. your brain, hormones, etc. and that is whole other set of problems.

Eating makes us feel better and if you are on poor sleep you might eat just to offset it.

Haha, I just learned this recently. It's on the menu in their app. I always order short now when I am in a mood for "unhealthy" drink

See my other response to sibling comment.

TLDR: weight gain is not from body using less energy but from your regulating machine being put out of balance.

Body on caffeine will still use more calories, but your brain on poor sleep will make worse choices and you will eat more just to offset unhappiness.

it's because sleep regulates the hormones that control your appetite

if you mean poor control of your body's natural drive to eat which is imperative to our survival, then sure

very few people can consistently control this "impulse" -- the best way to control it is to get adequate sleep and regulate your hormones

It's odd they didn't speak of caffeine itself as a supplement, and instead mentioned coffee.

Caffeine is a pretty common ingredient in any pre-workout, and you can get 200mg pills online cheaply.

Most energy drinks include other energy additives, which I think is where the dangers come from.

I can no longer drink red bull because it gives me really bad heart palpitations. Meanwhile, I can pretty much drink coffee all day without issue.

I was diagnosed with high BP very early in my life (23-24 yo). The doctor said it is okay to have everything in moderation but asked me to not touch energy drinks.

One means to keep functioning while sleep deprived is to eat more. I don't think it's really poor impulse control per se. It's a coping mechanism, sort of like the body shunting waste gas through the kidneys at high altitude because you can't offload them all via breathing out and they have to go somewhere, but that's not really the optimal way to do that and it has knock on effects because urinating to remove them also drags salt and other stuff with it, thus the need to drink more and get more electrolytes at altitude. (Edit: implicitly, weight gain us the equivalent knock on effect for eating more while sleep deprived.)

Caffeine, at least in large doses, is somewhat stressful on the heart by itself. It increases respiration and blood pressure and heart rate. A strong cup of coffee can give me minor palpitations.

I’m quite sure you’re mistaken as studied animals (usually rodents) do not behave the same as humans; and ultimately if our metabolic system becomes unbalanced then our body is suffering and will certainly attempt to overcompensate or risk damaging itself.

It matters very little if we burn fat faster, though I doubt it; it matters what the outcome is. In this case it does appear that people get fatter.

> More than two dozen epidemiological studies from around the globe looking at sleep deprivation and BMI in humans have shown association between decreased obesity and an increase in sleep duration.

> Data regarding impact of sleep deprivation on weight loss is conflicting in animals and humans. Sleep deprivation in rodent models causes weight loss despite hyperphagia [63–68]. These differences in rodents and humans may be explained by increased brown fat in rodents (rarely present in adult humans), which is metabolically more active and has been shown to increase thermogenesis and total energy expenditure [67]. In conclusion, epidemiological data is suggestive of weight gain with sleep deprivation though a few studies have also noted weight gain with prolonged sleep. Based on data on sleep duration and weight, sleep hygiene counseling could form an important tool in management of obesity.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2929498/

Almost seems like you're trying to sensationalize it by changing it to Red Bull, something that's actually pretty low in caffeine once you put marketing aside.

How about comparing it to Starbucks' regular hot coffee sizes?

- Short - 180 mg

- Tall - 260 mg

- Grande - 330 mg

- Venti - 415 mg

Is drinking a 12oz Tall at Starbucks really dropping your jaw?

> Seems like a lot when put in terms of Redbull,

Redbull doesn't actually have that much caffeine. A typically, 8oz cup of coffee has more caffeine than a redbull.

In fact, most "energy drinks" don't have that much caffeine. They have other ingredients that also provide energy.

It drops my jaw that anyone drinks that regularly.

In the industry the other ingredients are called “pixie dust”.

The heavy lifting is done by the caffeine.

That's a fair point, Starbucks coffee has more caffeine than an average cup of coffee. I'm sure many people (including myself) are not aware of that.

https://www.washingtonpost.com/opinions/five-myths-about-caf...

Thanks for digging these up. I agree OP would have to try to avoid first looking at coffee.

Not that odd if you consider science writing should appeal to as many as possible. The study itself used these workout pills you mention which were made from green coffee beans:

https://jissn.biomedcentral.com/articles/10.1186/s12970-020-...

How about sugar free energy drinks?

The amount of caffeine in a coffee depends on its extraction method, the grind, and to a lesser extent on roast. An espresso actually has much less caffeine than a cup of drip (60mg vs 200mg). Generally the longer you leave the beans exposed to water the more caffeine comes out, up to about 400 minutes when making cold brew. [1]

I doubt Starbucks is deviously out to over-caffeinate its customers (although if they were, they've got my vote!) but rather the difference is attributable to variations in their brewing process.

There's a limit to the amount of caffeine that can possibly come out of a bean, and so I would say that unless there's evidence they're spiking the brew, that Starbucks coffee is roughly the definition of an "average cup of coffee"

A Venti is 590mL and 415mg of caffeine, 700mg/L of coffee. Based on the chart in [1] that would be roughly speaking the midpoint of roast kind at the 150 minute mark making cold brew, 10g/100mL of coffee beans (Figure 1). Or approximately a dark roast, coarse grind hot brew (Figure 3).

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5740146/

Coffee is a lot more than caffeine, though. It contains a whole family of monoamine oxidase inhibitors, which have a host of effects on the nervous system.

That said, Red Bull very likely contains several types of flavonoids that also act as MAO-B inhibitors.

Coffee, on the other hand, contains both MAO-A and MAO-B inhibitors mainly from the Harmala alkaloid family. Some of the compounds are neurotoxic.

It seems like caffeine alone is an MAOI [1] and that decaf may not have the same effect [2] - very cool, thank you for sharing! I know there's a lot more in coffee too, so I'm looking forward to learning more.

[edit] Found this [3] which I assume is what you were talking about? Which I assume is the reason studies show it can act as an antidepressant [4]. Fascinating!

[1] https://pubmed.ncbi.nlm.nih.gov/23850513/

[2] https://www.jwatch.org/fw108796/2014/05/06/severe-hypertensi...

[3] https://pubmed.ncbi.nlm.nih.gov/16139309/

[4] https://www.medicalnewstoday.com/articles/313988#possible-ri...

Yes drinking two 12oz Talls at Starbucks every day is not good for your sleep.

Nespresso capsules have 60g for reference.

I get so tired of people equating espresso with high amounts of caffeine. I don't know where that originated... maybe because of the high temp / pressure extraction and the oils making it so much richer?

Well, this massive million drinker meta-analysis of coffee consumption (high levels, 5 cups a day) shows it significantly improves cardiovascular health. [1]

> A nonlinear association between coffee consumption and CVD risk was observed in this meta-analysis. Moderate coffee consumption was inversely significantly associated with CVD risk, with the lowest CVD risk at 3 to 5 cups per day, and heavy coffee consumption was not associated with elevated CVD risk.

[1] https://www.ahajournals.org/doi/full/10.1161/circulationaha....

> Is drinking a 12oz Tall at Starbucks really dropping your jaw?

Yes, absolutely. But I rarely consume caffeine so my experience is very different than yours.

The study used caffeine-naive individuals. That is, people without any caffeine experience or tolerance.

If you give two tall Starbucks coffees to a caffeine naive person, it will definitely cause some notable effects.

Frequent coffee drinkers tend to underestimate the impact of their caffeine tolerance. A seasoned coffee drinker consuming two of the strongest coffees on the market day after day is a different story than caffeine-naive individuals skipping straight to excessive doses of caffeine without any tolerance.

I don't see how this contradicts GP points.

The first point is that lack of sleep is associated with increased metabolism (increased energy expenditure at rest).

The second point is that the apparent link between weight gain and sleep deprivation could be explained by involontary caloric intake increase.

The sleep deprived body directs calories to fat storage.

A "cup" of coffee is officially 8oz and typically between 80 and 100mg.

Starbucks coffee doesn't really have a higher ratio of caffeine, just more volume than the official measurements.

That being said, I don't know anybody that drink 8oz cups of coffee.

Just use caffeine pills.

You left out the next part of your first quote:

> More than two dozen epidemiological studies from around the globe looking at sleep deprivation and BMI in humans have shown association between decreased obesity and an increase in sleep duration. These studies however do not establish a causal relationship.

The paper also mentions and agrees with who you were responding to:

> In summary, energy expenditure is reduced during sleep. Sleep deprivation appears to increase energy expenditure.

And finally in the conclusion:

> Paradoxically a similar U-shaped relation is also noted in several studies looking at the relationship between sleep and weight, with both short and long sleep leading to weight gain.

I may have missed it, but it doesn't appear a causal relationship was ever formed between metabolic dysregluation from sleep issues and weight gain. And since both less and more sleep were associated with weight gain, is sleep or the lack thereof just another symptom of stress and depression? Both of which often cause people to eat more.

Well it is much higher caffeine/volume, it's just that you (typically) drink a much lower volume of it.

A Starbucks Espresso shot has 75mg at 1oz.

A Starbucks dark roast (short size) has 130mg at 8oz - that is 16.25mg/oz.

That means the espresso has 4.6x the caffeine per volume. I’d say those people you’re tired of have something worth listening to.

https://globalassets.starbucks.com/assets/94fbcc2ab1e2435985...

mg/kg is a really weird unit to use without saying how many kg were consumed.

I think the point is that there is a difference between a cup of filter coffee and an espresso drink (Americano, latte, cappuccino etc) with the same volume. The first one is well... coffee, the latter contains only a shot or two of espresso and the rest of the volume in the cup is hot water/milk.

It's usually a unit of mg consumed per kg of body weight. (Hopefully 0 kg of which are being consumed.)

A lack of sleep leads to higher levels of cortisol and insulin, and decreases insulin sensitivity. This in turn physically prevents you from burning stored fat and leads to blood sugar being converted into fat for longer-term storage.

[1] https://www.sleepfoundation.org/physical-health/sleep-and-bl...

When used in contexts like this, it's mg of substance per kilogram of body weight. (with the assumption that the effect on metabolism etc somewhat scales with body weight, at least for people that are otherwise similar)

Oh. Thank you that makes more sense.

Do you mean mg rather than g?

The first meal after sleeping through the night is called "break-fast", after all.

Source? I drink a fair amount of coffee every morning (not any after 10am) and never had any sleep issues. The half life for caffeine is somewhere around 6 hours, no?

If they truly had no caffeine tolerance, iirc back when I first started ingesting more than I was used to it would make me a bit sick to my stomach.

But look who I was responding to: people think a single shot of espresso had more caffeine than a cup of coffee and that is not true.

Starbucks drinks typically have 2 shots (such as a grande mocha) which gonna be around the same amount of caffeine as a cup of coffee

Closer to 10 or 12 for many, it has a high variance in humans.

What does it do to every other disease? Doesn't say much if it looks at a single factor outcome.

Anecdata, but one tall (actually, even one short) at 8am will typically postpone the time I fall asleep by 4 hours and will typically reduce my sleep by an equal amount (i.e., I wake up at the same time despite falling asleep later).

I’ve run some experiments on myself, and this lasts for days at a time with one tall in the morning. If I keep at it for several days, I will crash early one evening, but still only sleep for 4 hours. It’s a nightmare for someone who typically sleeps 8 hours a night — I just feel fog-brained all the time. That said, workouts are super easy.

If I had a tall in the morning and evening on a regular basis, ugh... I can’t even imagine. I did this once for extra energy during a sports tournament (we won), but I basically had to drink myself to sleep each night.

Multiple doctors have told me that caffeine sensitivity varies from person to person, but I am on the unusually sensitive side.

I make coffee at home every day. I rarely go to places like Starbucks. I just measured my cup and it's 8 oz. I have one cup every morning.

there's also an approximate 30% difference in caffeine between Arabica beans and robusta beans, the latter having more caffeine.

Starbucks use Arabica, typically Italian or French espresso based drinks ha e been made with robusta or an Arabica robusta blend.

Starbucks coffee is not higher in caffeine compared to other cafés, it can actually be lower. The only sig ificant difference is portion sizes, like you mentioned.

Suffice to say, if there were meaningful risks from drinking normal amounts of coffee, it would be known by now. Its main drawback is that it makes people nervous and jittery if taken in excess.

Still, not too many people are drinking 6x Red Bulls at once, the scenario you brought up as an example. Meanwhile swathes of the world are pulling into Starbucks daily, many for their first time.

It's also not two 12oz coffees, it's one at 8am and another at 5pm. It just kinda seems like everything you write here is trying to cause a reaction and it feels manipulative.

You write all this just to reveal your actual point:

> If you give two tall Starbucks coffees to a caffeine naive person, it will definitely cause some notable effects.

Well, sure. We can all agree on that. And one of the notable effects is increased fat oxidation. Notice how uninteresting this observation is by itself. No need to dress it up as something more.

And anyone without a shockingly low caffeine tolerance also knows that one of the main ingredients in energy drinks is marketing.

Red Bull does nothing to most people that a cup of black coffee wouldn’t do. But the placebo effect is a helluva drug.

Coffee "cups" are measured in units of 6 oz:

https://www.triplebarcoffee.com/blog/how-many-ounces-are-in-...

One of the other major ones is that it can aggravate stomach problems like gastritis since both coffee (even decaf) and caffeine are said to stimulate stomach acid production.

There is also a breadth of studies that show consumption is bad - I wouldn't cheer just yet.

> They must have been feeling extremely energetic.

Perhaps even uncomfortably so: https://m.youtube.com/watch?v=qRuNxHqwazs

It's also relevantly the "C" in the ECA stack (ephedrine, caffeine, aspirin), which is a well-known supplement mix for bodybuilding - one specifically intended for fat burn.

back when i was drinking coffee (gut has changed with age... i can't drink it anymore), It never stopped me from sleeping, it just made me not want to go to sleep.

If I knew i really needed to sleep i could at any time.

Are you sure about that? I drink coffee all day long and in the evenings too. Doesn't affect me much. But some of the energy drinks gets me completely hyper so that I can't sleep.

I'm fairly confident none of them were million-person multi-year meta-analysis, although I'm always happy to be proven wrong. Do you have any broad, high-confidence studies you have in mind?

As someone that quit caffeine over quarantine, I cannot even imagine slurping half a gram of pure caffeine. I probably wouldn't sleep for a few days and I'm certain my teeth would chatter my filings out. I know it's an experiment and the people were consented, but man, that seems a bit ... mean. There's no way I can see having that much caffeine nowadays and not be a total wreck.

My understanding is that almost no one drinks 100% Robusta, since it tastes something between burnt tire, wood (not in a good way, in a 'trying to bite raw timber' kind of way) and rubber. However it's very commonly used as, in a positive interpretation, to accentuate the taste of Arabica since it produces more 'crema' on espresso, and in a negative interpretation, as an adulterant to make coffee cheaper to produce.

Here are some people writing about their experience of drinking 100% Robusta: https://old.reddit.com/r/Coffee/comments/6u2ef4/100_robusta_...

Yes, this is absolutely a normal amount. I'm an amateur/hobbyist marathon runner, and I usually take about 300mg pre-race in the form of coffee, and top up another 100mg in the form of a gel about once per hour. This is roughly in line with the amounts that are recommended by most race-day nutrition plans.

It varies a lot. I can drink a pot of strong coffee before going to bed. I do this regularly, never any problem sleeping.

> An espresso actually has much less caffeine than a cup of drip (60mg vs 200mg).

I think espresso has more caffeine per ounce than coffee does.

I quickly got addicted to Monster Energy drinks working at a Lowe's Hardware store across the street from a gas station; always been a caffeind. When the coffee ones came out I would do a 2 for and drink two during a break.

Anyway, at 21 I decided to use Jack3d, back when it was damn near Meth, it had DMAA in it. I didn't know this but being the 250lb 6' guy I was, slinging grills and landscaping stuff all day, I bucked up and took the "max dose" of it the first time.

Shit, I hit the gym, did extreme cardio on an elliptical for over an hour, lifted weights with some random ripped bros, and when my girlfriend came after work I stayed and ran further on the treadmill than her and her friend. Just the readouts from the elliptical and treadmill were almost 2200 calories.

Even afterwards when we went home I couldn't wait for us to shower before laying into her I still was so wired. A year later she was talking about that night...

Yea, I bet like hell someone that hasn't ever messed with stimulants can be turned sideways by them.

Source is Anecdotal. I respond very well to caffeine, though I am a bit dependant on it. My wife, nothing. I can drink a Monster and feel good.

I am 6' 240lbs, she is 4'6" and 90lbs. I can almost microdose caffeine depending on what I am doing... Sometimes it is an energy drink, sometimes cold brew undiluted, sometimes drop coffee. Shoot, at Starbucks I tend to be a "green eye" type of man and laugh when they ask if I want space for creamer.

Unless I pound back a massive amount of caffeine within 2-3 hours of bed I have no issues sleeping; then again, I have never had issues sleeping and the few times I do forget and drink caffeinated before bed, it only delays me a few hours or results in me reading a novel into the night.

Sleep problems as well and migraines.

I believe caffeine is both a treatment for, and a cause of headaches. [1] Excedrin for instance is a migraine treatment which includes Tylenol and caffeine.

[1] https://americanmigrainefoundation.org/resource-library/caff...

Reason it’s a treatment is helping absorption typically, but also, a lot of people’s headaches are from withdrawal so it helps in the way drinking a beer helps a hangover.

To everyone replying - "i can sleep even after drinking 100 coffees" - caffeine consumption affects certain stages of your sleep even though you might fall asleep, source is the book 'why we sleep'. All stages of your sleep are important, so if you are only getting rem sleep it is not good.