Episode 157 – Caffeine Questions and Misconceptions

Key Topics Covered

Today we are covering questions and misconceptions around caffeine inspired by a recent review titled “Common questions and misconceptions about caffeine supplementation”.
This is a peer-reviewed article from the International Society of Sports Nutrition. They do solid reviews like this occasionally where they cover a lot of common questions on certain topics.
We have chosen from the questions that they covered and then mixed a combination of the research they discussed as well as other points from the research as well.

Does Caffeine Dehydrate You?

The logic is based on caffeine being a diuretic.
But an increase in urine production doesn’t necessarily mean it dehydrates you.
For example, if you consumed 200ml of coffee and it increased urine production by 20ml, that could still be considered a net hydrating effect.
But even the topic of caffeine being a diuretic is complex.
In people who consume caffeine infrequently, it appears to be a diuretic on a consistent basis. In those who consume it habitually, dosages up to around 3mg/kg appear to not have this effect in many cases.
Having a lot more caffeine than that amount can have this diuretic effect, but it is still usually offset by the fluid it is consumed alongside.

Does Caffeine Decrease Body Weight and Fat Mass?‘

In people who had not been consuming caffeine regularly, it seemed to help weight loss a bit when it was added in.
Higher dosages were more linked with weight loss.
Caffeine consistently increased fat oxidation during exercise, although we know that isn’t the same as fat loss.
Results were inconsistent. Some research found differences, others didn’t.

The conclusion largely highlighted flaws in the research. They also mentioned that habituation to caffeine could reduce the impact on longer-term fat loss.

Reasons Why Caffeine May Help With Weight Loss:

The suppressed appetite may not be a isn’t a long-term consideration, so for habitual consumers, it is unlikely to have any real impact.
The increase in TDEE is real – but it is small. Is it really worth a high dose of caffeine, if you wouldn’t have been doing that for other reasons?
The fat oxidation part is largely irrelevant. Because even if we are burning more fat as fuel, without a caloric deficit this will not equate to weight loss.

Overall, in short-term studies, there is often a small favourable difference. But it is unlikely to matter long term.
Side Note: This also assumes it is not affecting sleep.

Does Habitual Caffeine Consumption Influence the Performance Response to Acute Caffeine Supplementation?

We definitely feel a change in caffeine tolerance, but whether this impacts performance is complex.
Although it’s a complex area, it is a simple practical interpretation.
Either caffeine habituation doesn’t have an impact, or it does. Research has had mixed findings.
In the cases where it has been concluded that it does, it seems like the simple solution is that going slightly higher caffeine still works effectively.
In this review, they suggested dosages as high as 6-9mg/kg for these situations.
For context, if somebody was 80kg, the top end of that range is 720mg, which is significantly high. That’s the equivalent of 4.5 500ml cans of energy drink. That would be a rare recommendation, but if somebody’s daily intake was very high already, this logic makes sense.

Does Caffeine Cause Heart Problems?

It is individual.
Chronic usage is leaning in favour of reduced issues. We also see other evidence of this with the research on coffee and longevity. But coffee seems to have benefits outside of caffeine.
The acute aspect has more concern though. In those who are not habitual consumers, caffeine can increase heart rate and blood pressure noticeably.
It can also increase what is known as myocardial oxygen demand, which can be a trigger for cardiovascular conditions.
This is why an individualized approach is relevant. It may be unreasonable to say caffeine by itself in normal dosages causes heart problems. But some level of caution is relevant for specific cases.

Should Pregnant Women Avoid Caffeine?

Many people talk about there being a cut-off of around 200mg for caffeine while pregnant.
But the actual consensus in the research is the lower the better.
Higher amounts of caffeine have always been linked with issues. But even lower amounts such as 100-200mg are still linked with issues such as increased risk of miscarriage, fetal growth restriction, low birth weight, as well as increased risks to the offspring, including cognitive development impairments.
Based on this research, the conclusion from solely looking at the data is that there is no safe cut-off and caffeine should be minimized or avoided.
It is best to discuss this topic with caution. It’s difficult, particularly when you factor in aspects like small amounts of caffeine in foods like tea or dark chocolate. The line has to be drawn somewhere, and based on the research it seems lower than 200mg, but right now the consensus is that the less the better.

Does Waiting 1.5-2 Hours After Waking to Consume Caffeine Help You Avoid the Afternoon “Crash?”

We’ve previously recorded a podcast on this topic specifically (Episode 120).
The quick version is that the impact on cortisol that is often proposed is not really that relevant.
In habitual consumers, the impact of caffeine on morning cortisol is significantly blunted. So it is more relevant to people who consume occasionally.
The adenosine-blocking abilities of caffeine are less relevant in the morning directly after waking, but that also doesn’t make it “bad”.
There’s no specific evidence that caffeine within 1-2 hours of waking causes a crash.
It is still acceptable to have multiple doses of caffeine in a day to help offset this, assuming you keep to an appropriate total dosage and set it up in a way so that it doesn’t impact sleep.

Summary:

If you are making sure you aren’t impacting aspects such as sleep or anxiety, it is okay to have a caffeine intake that suits you best.

Relevant Blogs / Resources

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