Most coffee drinkers don’t realize there are several disadvantages of black coffee. Now, that doesn’t mean you need to stop drinking coffee altogether — in fact, there are plenty of benefits of coffee — rather, it emphasizes the importance of preparing high-quality coffee in a way that will support your metabolism, blood sugar, and hormones.
In this article, we will discuss the composition of coffee, how your body metabolizes coffee, the benefits of coffee, the potential side effects of coffee, the disadvantages of black coffee, and a more metabolically-favorable way to drink coffee.
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Composition and Nutritional Value of Coffee
An 8-ounce cup of coffee contains:
- 0-5 calories
- 0g fat and cholesterol
- 116mg potassium
- 5mg sodium
- 0g carbohydrates, sugar, and fiber
- 0g protein
- 2% vitamin B1 (thiamine)
- 11% vitamin B2 (riboflavin)
- 2% vitamin B3 (niacin)
- 6% vitamin B5 (pantothenic acid)
- 1% vitamin B9 (folate)
- 2% magnesium
- 3% manganese
Absorption & Effects of Caffeine
Absorption and Metabolism of Caffeine
Caffeine from coffee is 99% absorbed within 37-47 minutes of ingestion. (1) The absorption of caffeine mainly takes place in the stomach and small intestine and is then transported to the body water and distributed to all tissues. Caffeine is metabolized into 13 different compounds in the liver which produce varying effects in the body. (2)
Effects of Caffeine
One action of caffeine is stimulation of the central nervous system (CNS). The effects of stimulating the CNS include increased energy, metabolism, alertness, concentration, heart rate, respiratory rate, and blood pressure. Other effects involve the cardiovascular, respiratory, and renal systems. (3) The level of effect varies between people based on genetics, activity of the liver enzyme cytochrome P450, weight, sex, and liver health. (2)
The Benefits of Coffee
Coffee can help you burn fat and lose weight by increasing your metabolism, especially when you are properly fueling your body with adequate amounts of carbohydrate and protein to support optimal metabolism.
Provides Minerals and Antioxidants
Minerals in coffee include potassium, magnesium, manganese, thiamine, riboflavin, niacin, pantothenic acid, and folate.
Antioxidants in coffee mainly include chlorogenic acids, tannins, lignans, and anthocyanin.
Chlorogenic acids prevent inflammation, edema, pain, liver tumor formation, and heart disease. They also slow the release of glucose into the bloodstream which helps to stabilize your blood sugar and prevent fat storage.
Tannins, lignans, and anthocyanin provide additional protection against free-radicals and oxidation. Of note, decaffeination reduces the total antioxidant activity of coffee. (2)
Lowers Heart Disease Risk
Chlorogenic acids present in coffee inhibit oxidation of low-density lipoprotein (LDL) and increase antioxidant action in the blood which can prevent the buildup of plaque in your arteries.
In addition, the chlorogenic acids in coffee can prevent and reverse high blood pressure.
Caffeine, on the other hand, can both decrease and increase blood pressure. For most people, blood pressure rises after coffee consumption, but the long-term effects appear to be minimal. Studies have shown that regular coffee drinkers do not experience a long-term rise in blood pressure, possibly due to increased tolerance, while those who rarely drink coffee may see long-term hypertensive effects.
Other studies suggest that the increase in blood pressure is mainly seen when caffeine is delivered intravenously and that the other compounds in coffee counteract the hypertensive effect of caffeine and additionally reduce the risk of stroke. (2,4)
Improves Insulin and Glucose Metabolism
Another benefit of the chlorogenic acids in coffee is improving your body’s ability to use blood sugar and preventing excess glucose production by the liver. Some positive effects of this include reduction of fasting blood glucose, increased insulin sensitivity, more stable blood sugar throughout the day, and consequently, prevention of type 2 diabetes. (4,5)
Reduces the Risk of Cancer
Coffee may reduce the risk of some cancers, including liver, breast, colon, rectal, prostate, endometrial, thyroid, mouth/throat, and melanoma. (8,9,10)
Improves Liver Health
Drinking four cups of coffee per day may help prevent liver cancer, cirrhosis, viral hepatitis, hepatic fibrosis, and fatty liver, along with decreasing high levels of liver enzymes. (8)
Coffee can relieve constipation and promote regular bowel movements in around 30% of people by increasing gastric motility and colonic motor activity. (11)
Protects Against Thyroid Disease
Reduces the Risk of Premature Death
Drinking up to 5 cups of coffee daily is associated with a decreased risk of death, including cardiovascular disease, neurological disease, and suicide. (13) Coffee may also prevent DNA damage and slow the aging process. (14)
Boosts Mental and Physical Performance
One study showed that drinking 5 mg/kg BW of coffee one hour prior to exercise improved endurance exercise performance. (15)
Another study showed significant improvements in mental alertness and performance after consumption of coffee. (16)
Improves Memory and Brain Health
Coffee can improve memory and brain health and reduce the risk of Parkinson’s disease, Alzheimer’s disease, and dementia. (17) It may also improve mood, decrease depressive episodes, and reduce the risk of suicide by stimulating the central nervous system and increasing the production of neurotransmitters. (18)
Helps Reduce Heavy Metal Consumption
Including coffee as a daily beverage can help limit the consumption of heavy metals. Coffee grounds remove heavy metals, like lead, mercury, zinc, copper, and cadmium, from the water it is brewed in. (19,20,21)
Additionally, coffee inhibits iron absorption when consumed with a meal. This may be especially beneficial if you are at risk for iron overload, whether due to a chronic iron overload disorder (like hemochromatosis), prolonged or excessive iron supplementation, or frequent consumption of iron-fortified foods. Iron overload increases your risk for infections and cancer, so it is worth taking note of your consumption. Humans only need 1-3 mg of iron per day for proper iron balance. (22,23,24)
Main Disadvantages of Black Coffee
Review the side effects and disadvantages of black coffee below:
Increased Cortisol and Stress
Drinking black coffee, especially without food, can cause an acute stress response in your body and, in response, excess cortisol to be released. This can lead to feeling jittery, anxious, and restless. (25)
Low Blood Sugar
Coffee increases metabolic rate which in turn increases the uptake of blood glucose by your cells which can cause low blood sugar if consumed in the absence of carbohydrates. Low blood sugar will trigger the release of cortisol and put the body in a catabolic state until your blood sugar rises to a normal level. (26,27)
Some people experience decreased feelings of hunger after drinking coffee. Believe it or not, suppressing your appetite is generally not a good thing. Your body requires a consistent source of fuel and prefers to get it from the food and beverages you consume. If you go several hours without eating because you don’t have an appetite, your body must break down your own tissues for energy to perform its many functions.
Coffee is naturally acidic and can cause side effects like heartburn, acid reflux, and stomach ulcers when it is consumed black and on an empty stomach. There are some lower-acid coffees available which can help alleviate these problems. Otherwise, you can implement the suggestions below to prevent stomach discomfort and long-term damage to your stomach lining.
How to Drink Coffee to Support Your Metabolism
Avoid the Disadvantages of Black Coffee With the Following Approach:
- Eat a nutrient-dense meal with carbohydrate, protein, and fat at least 15-20 minutes before you drink your coffee
- Fueling your body takes it out of stressed & catabolic state (where cortisol and adrenaline are running the show) and improves caffeine tolerance so you can avoid feeling jittery, anxious, restless, and lightheaded from low blood sugar and stress hormones
- Add a carbohydrate, protein, and fat source to your coffee to stabilize energy and blood sugar levels and prevent a stress response (if you ate a substantial meal, you may not necessarily need the additional energy and nutrients in your coffee; however, if you experience negative symptoms with your coffee, it’s worthwhile to try this approach)
- Carbohydrate: pure non-GMO cane sugar, coconut sugar, pure maple syrup, or pure honey
- Protein: collagen, gelatin, dry milk powder, or casein protein powder
- Fat: 1%/2%/whole milk, half & half, heavy cream, coconut milk, coconut oil, butter, or ghee
- Milk will provide carbohydrates, protein, and fat!
- Add a pinch of sea salt (if desired), like Maldon Sea Salt Flakes, for essential minerals, including sodium, chloride, potassium, magnesium, calcium, and more
Other Tips for a Healthy Cup of Coffee:
- Choose a mold-free, organic coffee and brew with filtered water
- Consume up to 400 mg of caffeine, or 3-5 cups of coffee per day, at most to avoid negative effects (28)
- Avoid drinking coffee too late in the day since caffeine can prevent you from getting adequate regenerative sleep which can put your body in a stressed state
- Most sources state that coffee consumption should be stopped four to six hours before you go to bed
- A little trial-and-error can help you determine what works for you
While there are several benefits of coffee, there are specific disadvantages of black coffee which can impact your stress hormones, blood sugar, appetite, and digestion. To prevent these potential side effects, be sure to consume adequate calories, carbohydrates, protein, and fat prior to drinking your coffee or give your coffee a boost by adding energy-promoting ingredients as listed above. Here’s to stable energy and a humming metabolism!