How much is too much caffeine? A nutritionist breaks down the numbers

Caffeine for athletes, pregnant and lactating women, and children all vary 

Photo by Stas Knop/Pexels

“Caffeine is the most consumed pharmacologic and psychoactive substance nowadays.”

Caffeine is well absorbed by the body. Peak levels in the blood occurs about 30 to 60 minutes after ingestion. It is one of the phytochemicals found in your favorite coffee bean, cocoa bean, and tea leaves.

What are the evidence-based benefits?

• Better concentration over a period of time
• Helps utilize fat as energy
• Reduces fatigue and improves endurance
• Lowers pain perception

But excessive intake of caffeine also shows adverse effects to the body. Some experience too much stomach acid production, nervousness, insomnia, irregular heartbeat, and anxiety. Caffeine withdrawal, as soon as 18 hours after the last dose, may also cause migraine, fatigue, and irritability. Though it’s still unknown why others do not experience such symptoms.

Then there are also the misconceptions. Some say caffeine causes dehydration, but this is totally not true. Though they act as a mild diuretic, recent research has demonstrated caffeine alone does not cause dehydration. But in hot humid weather and with long hours of intense training, excessive sweating, poor water intake, excessive caffeinated drinks can cause total dehydration.

Let’s take a closer look at how caffeine affects individuals based on the physical activity, age group, and level of tolerance.

Women

1. Pregnant women should limit their intake to 100mg a day.
2. Studies found that excessive caffeine intake may increase risk of miscarriage and low birth weight. Though dosage and to what extent caffeine causes harm is still under investigation, most recommendation is at 100mg a day or one to two cups of coffee a day.
3. Breast feeding and lactating mothers should limit coffee up to four cups a day. Almost anything a woman consumes may end up in her breast milk. Infants are smaller than women, and it will only take a smaller dose to have effects such as “caffeine jitters.”

Children and adolescents

1. The later they start, the better.
2. Coffee, tea, and soda are considered empty caloric food and has no nutritional value. Plus commercially prepared beverages can be loaded with sugar.
3. I recommend to start at the end of adolescence when growth is slowing down or almost complete. Though caffeine does not cause growth stunting, drinking more soda, tea, and coffee at an early age can affect a child’s total amount of calcium intake.
4. Maximum daily caffeine intake should be around 100-150mg a day or 2mg/kg body weight.

Athletes

1. Caffeine can enhance performance in endurance sports due to better concentration and lower pain perception.
2. Studies show that caffeine helps utilize the use of body fat as fuel, thus delaying glycogen (principal fuel for muscles) depletion–prolongation of exercise, especially for the first 15 minutes. Drinking caffeine before an activity can be beneficial, but it should be clear that in long hours of training (about two hours) or at endurance races like Ironman, properly fuel up with carbohydrates. Replenishing carb fuel needs to be every 15 to 30 minutes.
3. My tips for athletes is to abstain or gradually lower your caffeine intake three to four days before an event or competition to allow tolerance (repeated exposure to caffeine) to decrease and ensure maximum effect during race day.
4. Never try anything new on race day. If you plan to add caffeine in your strategy to last longer in a race, make sure it’s been part of your training months before a race. Practice how to abstain from caffeine like before a long ride training on a weekend. Note though that caffeine does not appear to be beneficial in short-term, high-intensity activities like sprinting.

Healthy adults

1. Most recommendation for healthy men and women re about 200-300mg per day to avoid negative side effects.
2. The most recommended maximum intake of caffeine is 300-400mg per day. But exactly how much caffeinated drinks and food are equivalent to the said recommendation?

400mg of caffeine is equivalent to the following:

Sources: World Health Organization, Healthychildren.org, Mayo Clinic, and NCBI-NIH