Coffee can curb appetite and boost metabolism, but will it really help you shed pounds? Find out what a nutritionist says.

By Cynthia Sass, MPH, RD
July 19, 2019

I have written before about the health benefits of coffee, as well as the potential perks of coffee naps, and why enjoying a cup  may lead to better fitness results. Now, coffee has become the central component of a weight loss plan some refer to as "the coffee diet."

What is the coffee diet, exactly?

The plan, based on the 2017 book The Coffee Lover’s Diet by medical doctor Bob Arnot, involves drinking a minimum of three cups of light roast coffee daily, due to its higher polyphenol antioxidant content. (Coffee polyphenols are linked to a reduced risk of a number of diseases, including type 2 diabetes and certain cancers.) In fact, you can have as much coffee as you’d like, either decaf or regular, as long as you hit the three-cup minimum.

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Dr. Arnot includes a good deal of research in the book about coffee’s ability to curb appetite, reduce fat absorption, boost metabolism, improve circulation, and burn fat. (Some of the benefits Dr. Arnot promotes are linked to caffeine, while others are true for regular or decaf coffee.) He advises skipping the sugar, cream, and milk, however, especially since the latter reduces polyphenol absorption.

He’s also particular about the beans, which are technically seeds inside coffeeberries, the whole fruit of the coffee plant. He recommends coffee selections from high altitude regions with rich, volcanic soil close to the equator, which produce the most antioxidants. Ethiopia, Kenya, Colombia, and Brazil rank at the top.

Apart from the three daily cups, the remainder of the plan is similar to other weight loss regimens. It involves avoiding refined carbs and processed foods while following many principles of the Mediterranean diet, with a calorie intake of around 1,500 per day. The book also includes recipes, much like a traditional diet book.

Can the coffee diet promote weight loss?

So is coffee really the solution to shedding pounds and keeping them off? Due to the aforementioned benefits, which are research-backed, it may help. Yet keep in mind a few important points.

First, sipping java throughout the day without regard to the rest of your diet will probably not yield results. Simply displacing healthy meals and snacks with black coffee can become a form of restriction that deprives your body of nutrients, zaps your mental and physical energy. In other words, it's not just the coffee itself but the balance of your overall eating pattern that's key to weight loss.

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For some people, coffee can trigger digestive irritation, including heartburn, and an upset stomach. Too much caffeine can also increase blood pressure, cause anxiety, rapid heartbeat, rebound fatigue, dehydration, and interfere with sleep.

I generally advise my clients to cut off all caffeine at least six hours before bed, and to listen to their bodies for signs that they may be overdoing it. It’s also important to consume a consistent amount of caffeine each day. This helps the body adjust, and can offset caffeine’s diuretic effect. Fortunately, decaf still offers a number of benefits, so if you want to try to increase your coffee intake for the polyphenol benefits, you may want to stick with "unleaded" entirely.

Bottom line: Coffee is good for you, especially without the add-ins. But it’s not a magic bullet, and too much can lead to unwanted side effects. If you’re a coffee lover, enjoy it in a healthy balance. But if you’re trying to lose weight, remain focused on the bigger picture. Eating clean, being active, getting enough sleep, and managing stress are still the pillars of healthy, sustainable weight loss.

