Morning coffee could boost your fat burning ability, a small study suggests

• A dose of caffeine may boost fat-burning during exercise, according to a small new study.
• About 240 mg of caffeine (or two cups of coffee) improved metabolism, particularly in the morning.
• Too much caffeine can have side effects, but up to 5 cups a day is generally safe for most people.

A morning cup of coffee could help wake up your metabolism, new research suggests.

Caffeine has been shown to increase your fat-burning ability during a workout, according to a new study published January 7 in the Journal of the International Society of Sports Nutrition.

Researchers from the University of Granada in Spain studied 15 healthy, athletic men aged 25 to 39 as they performed an exercise test. Prior to the test, they consumed either a placebo or 3 mg of caffeine per kilogram of body weight, in the form of colorless, unflavored powder.

The researchers found that participants were able to burn 11-13% more fat during exercise after the caffeine, compared to the placebo.

This could be particularly useful in the morning, when metabolism tends to be slightly slower than in the afternoon, the study found.

There's good evidence of caffeine's benefits, but dose matters

It's not clear from this study whether consuming more caffeine would enhance the benefits. The average dose consumed was about 240 mg of caffeine, the equivalent of roughly two eight-ounce cups of coffee.

The study also doesn't show how caffeine might affect people who already enjoy a daily cup o' joe, as the volunteers didn't regularly drink coffee or other caffeine sources before the study. There's evidence that habitual caffeine users develop a tolerance over time and experience milder effects as a result.

Too much caffeine, however, can lead to serious side effects like heart palpitations, difficulty breathing, and anxiety. Highly-concentrated powdered caffeine, often used in supplements, can make it easier to accidentally take too much, case studies have shown.

Coffee is a well-established way of getting the benefits of caffeine, for weight loss and more, with less risk of overdose. We know from previous research that it's safe to drink four to five cups of coffee a day for most people. Caffeine, in the form of coffee, has the added benefit of packing a hefty punch of polyphenols, plant-based compounds that may reduce the risk of chronic illnesses.