Statistics reveal that Americans love their coffee. In fact, 74% of people surveyed by Drive Research reported enjoying a steamy drink on a daily basis.
Scientists say that consuming coffee can be a healthy habit.
Drinking moderate amounts of coffee has been linked to lower rates of various health conditions, including type 2 diabetes and cardiovascular disease.
Now, we can add another benefit to the list. A study published October 1 at The American Journal of Clinical Nutrition reported that drinking coffee was associated with weight loss. However, there is a catch – it must be drunk unsweetened.
The study authors noted that coffee is often consumed with sugar, artificial sweeteners, cream, or non-dairy creamer.
The researchers wanted to investigate the relationships between how much coffee people drank, how much caffeine they consumed, and how their weight changed when considering what they added their coffee.
They also want to see if coffee or caffeine can reduce any weight changes caused by adding sugar.
The larger study included 48,891 people from the Nurses’ Health Study, 83,464 people from the Nurses’ Health Study II, and 22,863 people from the Health Professional Follow-up Study.
All participants were asked to fill out questionnaires about their food and drink consumption in the past year as well as in the next four years.
Data was collected on how much coffee they drank – both caffeinated and decaf – as well as what they chose to add to it.
The researchers then analyzed the data to see what relationships existed between coffee consumption and people’s weight throughout the study.
They found that an increase in coffee consumption of one cup of unsweetened coffee was associated with a weight loss of about 0.12 kilograms (0.26 pounds).
On the other hand, when people increased their daily sugar intake by one teaspoon in any food or drink, they gained 0.09 kilograms (0.20 pounds).
Cream and non-dairy creamer seem to have no effect on weight.
The research team further noted that changes in coffee or sugar intake had a stronger effect on weight in overweight and obese individuals and in young people.
They further found that caffeine also affects weight. When people’s intake increased to 100 milligrams, the amount of caffeine found in a cup of coffee, weight gain decreased by 0.08 kilograms (0.18 pounds).
Based on their findings, the scientists concluded that, while increasing coffee consumption helped people lose weight, adding a teaspoon of sugar canceled the effect.
Dr. Colleen Gulick, an exercise physiologist, explains that there are several ways in which coffee can affect weight.
One is its thermogenic effect. “Caffeine, a key ingredient in coffee, is known to stimulate thermogenesis, which is the process by which the body produces heat and burns calories,” he explained. “This thermogenic effect increases energy expenditure.”
The second way coffee can affect weight is by suppressing appetite. “Caffeine has been shown to have appetite-suppressing properties, which may reduce overall calorie intake,” he said.
The third property of coffee to look at, according to Gulick, is its metabolic effects. “Coffee contains bioactive compounds, such as chlorogenic acids and polyphenols, which are linked to metabolic benefits, including improving insulin sensitivity and glucose metabolism,” he said. “These effects may influence the regulation of body weight and contribute to weight loss.”
The fourth way coffee can influence weight loss, says Gulick, is by improving physical performance. “Caffeine has been shown to improve endurance and physical performance,” he said. “By increasing exercise capacity and intensity, regular consumption of unsweetened coffee may indirectly support weight loss efforts by increasing caloric expenditure during physical activity.”
And, finally, there are reasons outside of coffee itself that unsweetened coffee may help with weight loss, according to Michelle Saari MSc, RD. This may come down to the difference in calories you consume.
“People tend to fill their coffee cups with sugar, sweeteners, and lots of creamers,” he says. “If you add all of these to your daily cup of coffee and have multiple cups each day you can add hundreds of extra calories to a cup of coffee.”
Giving an example, Saari noted that a medium black Starbucks coffee with a shot of sugar-free syrup only comes in at 5 calories.
In contrast, drinking a caramel macchiato will give you 250 calories and 33 grams of sugar.
“So if you’re struggling to lose weight, consider switching to sugar-free syrup and avoid sugar-heavy drinks,” he advises.
Dr. Alex Foxman, medical director of Achieve Health and Weight Loss, said that, while coffee has many health benefits, it can also have negative effects for some people.
“For example, coffee can cause insomnia, anxiety, nervousness, palpitations, and gastrointestinal distress in some individuals,” he says,” especially those who are sensitive to caffeine or consume large amounts of it.”
Foxman added that coffee can interact with medications and supplements, including anticoagulants, antidepressants, iron, and calcium.
“Therefore, people who increase their coffee intake should consult their doctors if they have any medical conditions or take any medication that may be affected by coffee,” he advises. “They should also monitor their caffeine intake and avoid drinking coffee close to bedtime or on an empty stomach.”
While increased coffee consumption is associated with weight gain, researchers have found that adding sugar is associated with weight gain, largely canceling out the benefits.
Experts say that if you’re trying to lose weight, unsweetened coffee is the way to go.
If you are looking to increase your coffee intake, however, be aware that increased caffeine intake may have some side effects, such as jitteriness or insomnia. It can also interact with certain medications and minerals. You should consult your doctor if you have specific health concerns that could be negatively affected by caffeine.