Amount of Evidence: High Potential Benefits: High Safety: Reasonable
TABLE OF CONTENTS
What is coffee?
Coffee is the most popular source of caffeine in many parts of the world. The long-term health benefits of coffee are roughly comparable to yerba maté, although the polyphenol content in those beverages is quite different. In this article, we will look at the main benefits and side effects of coffee, and how to use it the right way.
Potential benefits
It is important to note that all of the potential benefits mentioned below are dose-dependent. In general, the more coffee you drink, the more pronounced these effects will be. However, some of them do reach a plateau at a certain point. We will discuss how much coffee to drink later in this article.
Major benefits
Reduced fatigue and sleepiness – Caffeine, the main stimulant in coffee, has a similar molecular structure to adenosine and because of that, it is able to enter and fill adenosine receptors. When adenosine molecules enter the receptors, they send a signal to the body that it is time to fall asleep, making you relaxed and sleepy. When caffeine fills the receptors instead of adenosine, adenosine molecules cannot enter the receptor for as long as the caffeine remains in the system, which delays the sleep-inducing effect of adenosine.
Reduced inflammation – Coffee appears to decrease some inflammatory cytokines.
Increased power output – This benefit is also caused mainly by caffeine and applies to all forms of high-intensity exercise, including sprints and strength training.
Fat loss – Coffee appears to be quite effective for fat loss because of the synergy between the antioxidants in coffee and caffeine. Neither of those components is very effective on its own but the combination of these compounds is what makes coffee very useful if you wish to burn fat. It seems to be the case that caffeine can increase metabolic rate indirectly by increasing power output during exercise, which would make coffee more effective for fat loss when you drink it before exercise. Also, this would mean that coffee is more beneficial for people who exercise than for those who do not, which does appear to be the case.
Improved heart health – Long-term consumption of coffee has been associated with improved heart health and reduced risk for heart disease and other cardiovascular diseases.
Antioxidant effects – The polyphenols in coffee have been shown to notably decrease oxidation in the body. This effect may be the main reason why coffee consumption appears to lower the risk for cancer.
Increased aerobic capacity – Similarly to most other beverages containing caffeine, coffee significantly increases aerobic capacity. This effect has been studied primarily in runners but applies to all forms of endurance training (cardio). This benefit is mainly due to the stimulant effect of caffeine.
Up-regulation of dopamine – Caffeine in coffee significantly increases the upregulation of some dopamine receptors. Because of this, it makes you able to experience more dopamine-related effects without significantly increasing dopamine levels in your system. Caffeine also increases dopamine levels to some extent but the increase is small.
Minor benefits
Improved cognition – Coffee appears to slightly improve cognition independent of caffeine’s effects. This benefit is most notable in people who have a poorer cognition at baseline but also applies to cognitively sharp individuals to a smaller extent.
Improved cholesterol levels – The polyphenols in coffee have been shown to increase HDL cholesterol but do not appear to lower LDL cholesterol.
Improved skin quality – A high intake of the beverage and its polyphenols leads to an improvement in skin quality. Specifically, these polyphenols are able to reduce acne.
Improved dental health – Tea has been shown to have anti-microbial properties and can protect your gums from bacterial infections. This effect likely applies to coffee as well.
Reduced muscle soreness – This benefit has more to do with the antioxidants in coffee than caffeine. The effect is most notable if you overtrain or if you are a beginner at resistance training.
Neuroprotective effects – The polyphenols in coffee have been shown to protect the neurons in the brain from toxins and aging-related damage.
Increased adrenaline and noradrenaline – This effect is caused by caffeine but lowered to some extent by the antioxidants in coffee. Depending on how you look at it, this effect can either be viewed as a benefit or as a negative. The increase in those two neurotransmitters can be very useful if you want to increase alertness and exercise performance.
Increased longevity – Coffee usage has been associated with an increase in longevity in animal studies. Unfortunately, there are not enough human studies yet to know what the effect of coffee is as far as slowing down aging.
Protection from DNA damage – The polyphenols in coffee can reduce DNA damage. This effect appears to be most notable in unhealthy individuals, such as diabetics.
Chelation of heavy metals – The antioxidants and caffeine in coffee have the ability to bind heavy metals and help detoxify them.
Reduced appetite – Coffee can reduce appetite for two reasons. One is the beverage’s caffeine content and the other one is its ability to reduce gastric emptying after meals. Unfortunately, this effect is often overhyped and the studies on it are not too high-quality. Coffee does work great in this regard for some people but certainly not everyone.
Improved insulin sensitivity – Coffee has mixed effects on insulin sensitivity but in general, it usually leads to an increase. This effect is most notable in unhealthy people with insulin resistance. The polyphenols found in the beverage have also been linked to a reduction in fasting blood glucose levels but not fasting insulin levels. While caffeine can actually worsen insulin sensitivity, this effect only occurs acutely when caffeine is combined with a meal rich in carbohydrates. Insulin sensitivity then quickly returns back to normal and is not affected negatively in the long term.
Increased endurance – Rating of perceived exertion (RPE) decreases in most people when they drink coffee before an exercise session. Caffeine has also been shown to increase training volume (the total work done during an exercise session) in both endurance and strength training.
Improved reaction time – While this benefit is small and the evidence is rather limited, caffeine in the beverage has been shown to improve reaction time in certain situations.
Increased blood flow – Coffee causes a slight increase in blood flow. This effect applies to both the antioxidants in coffee and caffeine. When taken together, the benefit is multiplied.
Increased subjective well-being – Numerous studies have shown that coffee and other sources of caffeine significantly improve mood and well-being in the short term. The long-term effects on well-being have not yet been established and depend greatly on the individual. It appears that caffeinated beverages can both increase and decrease long-term well-being, depending on how one responds to caffeine, what time of day one consumes the beverages, etc.
Reduced iron absorption – The caffeine and polyphenols in coffee can lower iron absorption by up to 30%, depending on how close to your meals you drink the beverage. This can be seen as a benefit for those who have too much iron in their bloodstream, which is just as common (if not more common) as iron deficiency.
Increased thermogenesis – Coffee increases the body’s ability to generate heat from brown fat. This is the main effect responsible for fat loss.
Liver health – The evidence is somewhat weak in this regard. However, there is at least some amount of data that shows coffee may be beneficial for liver health in the long term.
Increased metabolic rate – Coffee can speed up your metabolism. This mostly has to do with caffeine and its synergistic effects with polyphenols. It seems to be the case that caffeine in the beverage can increase metabolic rate indirectly by increasing power output during exercise. However, the beverage may slightly increase metabolism even in those who do not exercise.
Unproven benefits
The effect of coffee on these parameters has either not been sufficiently researched or the science shows little to no efficacy in these areas.
Testosterone – Polyphenols in coffee have the potential to both increase and decrease testosterone, depending mainly on the dose but also some other factors. Usually, low amounts of coffee appear to slightly increase testosterone levels in most people while high amounts appear to decrease it, especially if your testosterone levels are already high. Also, there is a good amount of evidence on the relationship between caffeine and testosterone. A 12% increase in testosterone was noted in trained individuals who took 250 mg of caffeine prior to a training session. Although 12% sounds like a lot, this is a relatively small increase compared to many other supplements that have been shown to increase testosterone. Also, this benefit is dependent on physical activity and does not apply to individuals who do not exercise.
Heart rate – The polyphenols in the beverage can indirectly lower heart rate (by lowering blood pressure and helping you burn fat) but caffeine has been shown to slightly raise the heart rate. An increase is highly dose-dependent and has been noted especially in people who are very sensitive to caffeine. Even then, the effect of caffeine on heart rate is not significant in healthy people. So overall, coffee doesn’t have a notable impact on heart rate.
VO2 max – While green tea and many other types of tea have been associated with a slight increase in VO2 max, this effect has not been observed in those who drink coffee. However, caffeine may indirectly increase your VO2 max in the long term by increasing power output and making you more effective at aerobic and anaerobic exercise.
Memory – The evidence is highly mixed. From the studies we have so far, there seems to be a mild increase in spatial memory but a decrease in working memory associated with caffeine. The negative effect on working memory may be due to overstimulation.
Bone health – Coffee does not significantly influence bone mineral density.
CRP (C-reactive protein) – No strong connection between coffee and CRP has been observed.
Triglycerides – No significant influence on fasting or postprandial triglycerides has ever been noted.
Possible side effects
Most of these side effects are associated with caffeine and do not apply to decaffeinated coffee. Also, these side effects are dose-dependent and the risk for them increases (most often linearly but sometimes exponentially) as the dose is increased. Some of the side effects are relevant only at very high doses.
Anxiety – This effect varies greatly from person to person. Your genes and your psychological state play a huge role in whether or not coffee is likely to make you anxious.
Shaking – This is one of the effects of caffeine that seem to increase exponentially as you increase the dose. The shaking could in one way be viewed as a positive effect as it might be a form of somatic releasing. However, we do not know yet whether or not the shaking induced by caffeine can lead to improved psychological well-being in the long run. It may simply be an unpleasant sign of overstimulation.
Yellow teeth – Beverages that contain caffeine can turn your teeth yellow if consumed regularly. This effect seems to be more problematic in tea than in coffee.
Worsened sleep quality – Caffeine can make it harder to fall asleep and shorten the time you spend in deep sleep. This effect can occur even if you drink caffeinated beverages earlier in the day, as the half-life is about 5 hours and can be as long as 9.5 hours in people who metabolize caffeine slowly.
Disruption of circadian rhythms – This can happen for two reasons: either because of the effect caffeine has on your sleep or because of disrupting the natural morning cortisol rise when you drink caffeinated beverages in the first 90 minutes after you wake up. We will look into this effect more deeply later in the article.
Dependence – When you consume caffeine on a regular basis, more adenosine receptors are formed, making you dependent on caffeine. You will then need more and more coffee or other caffeine sources to get the same effect.
Caffeine withdrawal – When you stop drinking coffee or other sources of caffeine, the adenosine receptors will start getting broken down, which leads to the symptoms of withdrawal, such as headaches, fatigue, and getting angry and annoyed easily.
Decreased absorption of certain minerals – The polyphenols and caffeine worsen the absorption of iron and zinc, which may and may not be a concern to you. Since a somewhat high percentage of people are deficient in those two minerals, you may want to avoid caffeine close to your meals to minimize this effect, especially if you are experiencing signs of deficiency in these two minerals. On the other hand, this effect can also be viewed as a benefit since many people have too much iron in their bloodstream, which can lead to iron toxicity and faster aging.
Adrenal fatigue – Caffeine can cause adrenal fatigue and adrenal burnout if you regularly consume it to the point where you do not allow the body to rest enough and repair the adrenals. Adrenal fatigue can lead to a variety of health problems. This is perhaps the main reason to cycle caffeine and stop using it for a week or so every once in a while.
Increased blood pressure – While the rise in blood pressure should not be a concern for healthy people who stick to normal amounts of coffee, those with already high blood pressure should be aware of this potential side effect and probably limit their caffeine intake.
Increased cortisol – The beverage can also increase cortisol levels to some extent.
Nausea – This side effect usually only happens if you drink a very strong cup of coffee and is caused mainly by the polyphenols in it. Nausea caused by the beverage is not linked to stomach damage and is by no means dangerous.
Diarrhea – This is the most common short-term side effect as it can happen even at low doses.
Esophageal cancer – While the antioxidants in coffee can protect you against cancer, the beverage can also increase your risk for esophageal cancer if you drink it the wrong way. This possible side effect is not related to the coffee itself but to hot water. If you drink the tea while it is too hot (60°C / 140°F or more), it can damage your esophagus and increase your risk for esophageal cancer.
Fillers in coffee – This is not a problem connected to the beverage itself but some brands sell coffee that contains sweeteners and other potentially harmful chemicals. Also, it is important to note that coffee with sugar or milk in it can easily cause more harm than good. Many of the benefits above do not apply if you add these into your cup.
Who should not drink coffee?
You should probably avoid coffee if you:
have a zinc or iron deficiency (polyphenols and other compounds in coffee can reduce the bioavailability of these minerals)
have difficulty falling asleep and staying asleep in the evening
are pregnant
are very young
want to avoid the teeth-yellowing effect
feel anxious or jittery after drinking coffee
already consume a lot of caffeine from other sources
prefer the taste of regular tea (since some types of tea appear to be more beneficial than coffee)
Who will benefit the most?
You should consider drinking coffee if you:
want to lose fat
are a serious athlete trying to maximize exercise performance
need to increase energy and alertness on certain occasions
have too much iron in your system
How much coffee should you drink?
People often give very simplified answers, like 1-3 cups a day. However, anywhere from 0-5 cups can be a good amount to consider, depending on what you want to get out of coffee.
Even one cup can provide notable benefits related to the polyphenols. However, the benefits do not seem to plateau even after 3 cups a day.
To find out how much of the beverage you want to drink, you have to first figure out what the best dose of caffeine is for you because caffeine is the primary stimulant compound in the beverage responsible for most of the short-term (and possibly also long-term) effects of coffee.
All of the numbers below apply to caffeine. Since coffee’s content is typically around 135 mg, you can divide the doses below by 1350.
How much caffeine you should ingest depends on many factors, such as your weight, how sensitive you are to caffeine, and how fast you metabolize the compound.
You should also take into consideration your personal goals and what you want to get from the stimulant. For example, if you wish to maximize exercise performance, that will require a different approach to dosing than if you simply want to increase alertness and reduce fatigue.
Most scientific studies on caffeine use doses of 4-6 mg/kg. However, this dose seems to be a little too high unless you are a serious athlete and want to maximize power output during exercise.
If you are an average individual with an average tolerance, a dose of 100-200 mg a day appears to be ideal for most people. This dose will still allow you to be more energetic and productive but it will not impact your sleep negatively if you take it (or drink it) early in the day.
If you have been taking higher doses of caffeine on a regular basis, you may be able to consume more than 200 mg without the negative impact on your sleep.
The best way to determine whether or not you can handle higher doses is by listening to your body. Specifically, how easy or hard it is for you to fall asleep is a good indicator of whether or not you should cut back on caffeine.
If you experience more anxiety after taking the stimulant, that is a sign you may want to cut back on it and lower your dose. So caffeine dosing depends heavily on an individual and varies greatly from person to person. To know the optimal dose you should take, you will need to experiment a bit.
It is important to note that you do develop tolerance to caffeine over time and the higher the dose you are taking, the sooner the tolerance will develop and the more intense it will be. Fortunately, you can get rid of the tolerance by going through a caffeine cycle at least once in a while.
Probably the best caffeine cycling protocol to reset your tolerance for the compound is going cold turkey for a week every 3 months. While the week without the stimulant will probably be unpleasant (most people experience headaches, low energy, and get agitated very easily), the pain is worth going through if you wish to maximize the benefits of caffeine.
If you have been consuming caffeine every day or nearly every day for many years, you will probably need more time than a week to get back to baseline and become fully sensitive to the stimulant. In the most extreme cases, this takes up to 3 months. However, 1-2 weeks should lead to most of the restorative effects.
Also, if you wish to get through the withdrawal phase faster, one very effective way to do it is sleep banking, where you try to sleep as much as possible (even if it’s 12-16 hours a day) to allow your body to get back to baseline faster.
Fortunately, there is no way you would drink so much tea that it would lead to toxicity. Doses of 20-40 mg/kg of caffeine can be toxic. Even 10 mg/kg is too much and this amount would almost certainly cause more harm than good for the vast majority of people. But to achieve this amount, you would have to drink at least a couple dozen cups of tea.
So to give a general recommendation, 2 cups of coffee should provide many benefits without meaningful side effects. But again, this recommendation is extremely simplified and does not apply to everybody.
Best time to drink coffee
The best time to drink caffeinated beverages is around 90 minutes after you wake up.
This is because in the early morning, there is a natural increase in cortisol responsible for waking you up and getting you ready for the day. By drinking coffee, tea, yerba, or ingesting caffeine from other sources right after you wake up, you would interrupt this natural increase in cortisol and your body would not be producing as much of it in the following days. This would lead to increased production of cortisol at the wrong times of the day, such as in the evening. After the morning cortisol increase which typically lasts for 90 minutes, you want to drink coffee as soon as possible so that most of it leaves your system before it’s time to go to bed.
The half-life of caffeine is on average around 5 hours but this depends heavily on your genes. Some people metabolize the stimulant very fast but some are so-called slow caffeine metabolizers. The half-life can therefore last anywhere from 1.5 to 9.5 hours. If you have your genetic results available, CYP1A2 is the main gene that regulates caffeine metabolism and how fast your body gets rid of the compound.
As a general rule of thumb, drinking coffee after 2 pm is not a good idea unless you know you are a fast metabolizer. But obviously, this advice is very simplified and doesn’t take into consideration all the variables.
Again, the best way to determine whether or not coffee is damaging your sleep is to listen to your body and specifically look at how easily you fall asleep and how refreshed you wake up.
While drinking coffee early in the day but not in the first 90 minutes after waking up is the most important timing rule to keep in mind, there are three more things to consider.
One of them is exercise. If you wish to use the stimulant to increase exercise performance, take it at least 45 minutes before your exercise session. If you exercise in the evening, forget about this recommendation.
The other thing to consider is spreading caffeine and not consuming all of it at the same time. This will make the energy-increasing effects more stable throughout the day and it will also lower some of the potential side effects.
Another thing to consider is coffee’s effect on iron and zinc absorption. The polyphenols and caffeine in the beverage can decrease the bioavailability of iron and zinc which could be both an issue and a benefit, depending on how much iron you have in your bloodstream. If you experience symptoms of anemia, do not ingest caffeine close to your meals.
Interactions with other supplements
Caffeine The polyphenols in coffee negate some of the potential side effects of caffeine. The combination also appears to be quite effective for fat loss and a few other effects. However, beware that supplementing with extra caffeine if you already drink coffee can easily make you overstimulated and cause many of the side effects we talked about.
Vitamin C Vitamin C appears to enhance the absorption of antioxidants in coffee. It can also protect iron from becoming less bioavailable after you drink the beverage.
Danshen This Chinese herb increases the half-life of caffeine by 12-16%.
Iron Since coffee’s antioxidants and caffeine inhibit the absorption of iron by around 10-50%, they may increase your iron needs. If you notice a sign of deficiency or are prone to it, you may want to increase your iron intake and supplements are one way to go. Do not take iron together with coffee though, so the absorption isn’t worsened. Also, do not take this as a call to action to start taking iron if you are not deficient because some people tend to have too much iron in their system. Excess iron in the blood can also lead to health complications.
Zinc The same that has been said about iron also applies to zinc. The only difference is that zinc absorption does not get affected by the polyphenols in coffee, but caffeine does lower zinc absorption.
L-Theanine L-theanine naturally occurs in tea and is able to reduce the negative effects of caffeine, including anxiety, jitteriness, and even the potential negative impact on sleep to some extent. If you consume a lot of caffeine, it is highly recommended to combine it with 100-200 mg of l-theanine. Besides theanine’s ability to lower the side effects of the stimulant, the combination is also very effective at improving focus and attention. It has also been shown to protect people from cognitive decline to some extent.
Quercetin Quercetin is able to increase the absorption of polyphenols in coffee.
Soy isoflavones The combination likely leads to AMPK activation, which may have a positive effect on increasing lifespan.
Taurine When used together, the effects of both coffee (especially the caffeine in it) and taurine get slightly enhanced.
EGCG EGCG and green tea catechins in general can reduce the blood pressure increase from caffeine. It also reduces its effects on adrenaline and noradrenaline. Overall, EGCG leads to a smoother peak of the stimulation effect.
Whey protein Whey protein negates many of the beneficial effects of coffee.
Alcohol As a stimulant, caffeine can negate the depressant effect of alcohol, making the drinker feel as if he is not impaired. This makes the drinker likely to drink more.
Propranolol Propranolol has been shown to reduce caffeine’s thermogenic effects, making it less effective for fat loss. On the other hand, propranolol can reduce sperm motility which is countered by caffeine.
Other sources of caffeine
Caffeine supplements – Even though many of the benefits above also apply to caffeine supplements, it is not the preferred way to take the compound because you would miss out on all of the other benefits of guarana, tea, coffee, or other sources. Caffeine supplements are rarely worth it unless you are a serious athlete or hate the taste of caffeinated beverages. Even in those cases, guarana supplements or tea and coffee extracts would be much better.
Guarana– Guarana (Paullinia cupana) is a plant traditionally used in and around the Amazon rainforest. The seeds of Paullinia contain more caffeine than coffee or any other plant in the world (3.6-5.8% of their dry weight is caffeine).
Coffee – The caffeine content of coffee varies greatly from cup to cup. Generally, a regular cup of coffee contains between 40 and 180 mg, with the average being around 135 mg. So if you drink coffee that is not too intense, you can probably count one cup as 135 mg. Decaffeinated coffee only contains about 2 mg per cup.
Green tea – An average cup contains around 20 mg of caffeine and 50-100 mg of EGCG.
Decaf green tea – Decaffeinated green tea contains on average 1-2 mg of caffeine and 60 mg of EGCG per cup.
Matcha green tea – Matcha is significantly higher in both caffeine and catechins than other forms of green tea. Or, more precisely, you get to consume more of these since you swallow the powder.
Pu-Erh – Pu-Erh is comparable to black tea as far as its caffeine and catechin content.
Black tea – Black tea contains about 2 times as much caffeine as green tea, so on average 40 mg. Unfortunately, it is not very high in catechins and only contains around 10 mg of EGCG per cup.
Oolong tea – Oolong tea’s caffeine and catechin content is somewhere between green and black tea. An average cup contains 30 mg of caffeine and 40 mg of EGCG.
White tea – White tea has around the same level of catechins as green tea and contains an average of only 10 mg of caffeine per cup. This is a very good thing because it allows you to drink a lot of white tea and reap more benefits connected to EGCG and other catechins in it.
Yellow tea – This type is extremely similar to white tea.
Cacao – Cocoa powder has around 0.21% caffeine by weight. Therefore, one gram contains an average of 2.1 mg.
Yerba maté – Yerba maté has a much higher caffeine content than regular tea. Typically, an average cup of yerba maté contains about 80 mg of caffeine.
Soda and energy drinks – This is undoubtedly the worst way to consume caffeine, mainly because of the sugar and/or artificial sweetener content in these drinks. There are brands on the market that sell relatively harmless energy drinks sweetened with stevia, xylitol, or erythritol. While these are definitely a better choice than regular energy drinks, they are still not better than coffee, tea, or other natural sources. As for caffeine content, energy drinks almost always contain around 30 mg per 100 ml, and Coke contains around 10 mg per 100 ml.
Because of coffee’s popularity, you can buy it in pretty much any food store.
Amazon is also a great option for ordering coffee in many countries. They offer some very affordable tea that is backed by many positive reviews. Also, you can choose from a wide range of brands there without having to spend time searching through other markets on the internet.
FAQ
An average cup has 135 mg of caffeine. However, this depends greatly on the type of coffee, how fresh it is, and how intense you make the beverage.
It is important to note that you do develop tolerance to caffeine over time and the higher the dose you are taking, the sooner the tolerance will develop and the more intense it will be. Fortunately, you can get rid of the tolerance by going through a caffeine cycle at least once in a while.
Probably the best caffeine cycling protocol to reset your tolerance for the compound is going cold turkey for a week every 3 months. While the week without the stimulant will probably be unpleasant (most people experience headaches, low energy, and get agitated very easily), the pain is worth going through if you wish to maximize the benefits of caffeine.
If you have been consuming caffeine every day or nearly every day for many years, you will probably need more time than a week to get back to baseline and become fully sensitive to the stimulant. In the most extreme cases, this takes up to 3 months. However, 1-2 weeks should lead to most of the restorative effects.
Also, if you wish to get through the withdrawal phase faster, one very effective way to do it is “sleep banking”. Basically, what that means is you try to sleep as much as possible (even if it’s 12-16 hours a day) to allow your body to get back to baseline faster.
The first effects will become notable around 15 minutes after ingestion. You can expect the peak effect to occur around 45-60 minutes after you drink coffee.
Coffee does lose potency over time. Usually, you can expect it to be just as fresh as when you bought it for 6-12 months if you store it well.
Keep coffee in a cold, dark, and dry place and it should remain just as potent for a few months or even years.
Unfortunately, coffee does not contain L-theanine. You can, however, take it in a supplement form when you drink coffee. These two go very well together.
The half-life of caffeine can be anywhere from 1.5 hours to 9.5 hours, depending mainly on your genes. The average half-life is 5-6 hours. Therefore, it takes a few days for the compound to fully leave your system but the effects will be less and less potent.
As for the polyphenols in coffee, the peak plasma concentrations are reached 1-2 hours after you drink it. After that, the concentrations start slowly diminishing until they become undetectable, which usually takes around 24 hours.
The main compound that can cause trouble if you drink high amounts of coffee is caffeine.
Doses of 20-40 mg/kg of caffeine have been shown to be toxic and are not recommended to anybody. This would mean 1 cup for every 5-10 kilograms of body weight. So you do not have to worry about caffeine toxicity from coffee.
However, even though it is nearly impossible to overdose on coffee, drinking too much can lead to anxiety, agitation, sleep problems, and all the other side effects connected to caffeine.
Therefore, it is recommended to stay below 3-4 cups a day.
Also, if you are pregnant or suffer from cardiovascular health issues, you may want to decrease your caffeine intake even further.
To stay on the safe side, you want to drink no more than 1 cup a day.
Here is a brief explanation of why the withdrawal happens:
Caffeine has a similar molecular structure to that of adenosine and is, therefore, able to enter and fill adenosine receptors. When adenosine molecules enter the receptors, they send a signal to your body that it is time to sleep, which makes you relaxed and sleepy. When caffeine fills the receptors instead, adenosine molecules cannot enter the receptors until caffeine leaves them, which postpones the sleep-inducing effect of adenosine. Because of this, your body starts creating more and more adenosine receptors that adenosine can fit into, making you more reliant on caffeine. When you stop consuming caffeine, the adenosine receptors will start getting broken down, which leads to the symptoms of withdrawal, such as headaches, fatigue, and getting angry and annoyed easily.
Fortunately, it takes only around a week to get rid of the excess adenosine receptors.
It takes about a week to get through the withdrawal and become fully sensitive to the stimulant again. The first days of the withdrawal phase are usually the worst but once you get through them, the symptoms of withdrawal will gradually get less and less intense.
There are many brands and types of coffee on the market and they all taste slightly different. But in general, coffee has a bitter taste. The longer you steep it in water and the higher the temperature of that water, the more bitter it will taste.
A higher temperature is a way to go because it will allow more of the beneficial compounds to get dissolved in water. While some compounds will get destroyed by high heat, this is not a big concern and a higher temperature is still a better way to go.
So to optimize the health effects of black tea, pour boiling water on it and let it steep in the water for as long as possible.
All of these have the potential to be beneficial for long-term health. Which of these beverages is better for you depends on many variables.
One important factor to take into consideration is that coffee has considerably more caffeine per cup than tea and yerba. Compared to green tea, one cup of coffee is usually 2-7 times higher in caffeine.
As for the health benefits, one cup of average coffee can be just as beneficial as one cup of average tea. However, this means that tea is significantly more beneficial than coffee per mg of caffeine.
So if you look at benefits per cup, the difference is not too big and will depend on the quality and type of coffee or tea you are drinking. If you look at the benefits per caffeine, tea is almost always going to be a clear winner.
Yerba is somewhere between the two as far as its polyphenol content, caffeine content, and long-term effects.
Also, beware that this answer is extremely simplified. Coffee has a considerably different chemical structure than tea and leads to different health effects. This answer applies to general health but not to all areas of health. In some areas, tea is significantly more effective and in other areas, the opposite is the case.
No, it is perfectly fine to drink coffee during a fast. In fact, the antioxidants and caffeine in it are actually going to increase some of the benefits of fasting. One caveat though is that drinking coffee with sugar or milk in it would certainly break a fast.
References
Most of the information provided in this guide is based on scientific research that can be found and verified in the PubMed medical library. We excluded from consideration studies that are either confounded or have a high conflict of interest.
Anecdotal evidence (from reports on Reddit, YouTube, and other sources) is also taken into account unless it contradicts scientific research.
