I remember the first time I submitted a meal diary to my personal trainer. As I anxiously awaited his feedback (and judgment). I wondered what he would scold me for first—the toast I ate for breakfast every morning. The muesli bar I snacked on every afternoon? The pizza I ate religiously every Friday night? But to my surprise, his first comment read: “You’re drinking three coffees a day? Why?” He explained that this was probably the biggest thing stalling my weight loss. I was flummoxed. I thought coffee was a healthy food, with all the longevity-boosting antioxidants. Plus, I had it with almond milk!
But turns out my trainer was onto something. While caffeine has health benefits (drinking lots of it has been found to reduce your risk of conditions like type 2 Diabetes and Parkinson’s disease), overdoing it on the java can impact weight loss—and even make you gain weight! Here’s why.
Why drinking too much caffeine can stall weight loss.
The average person drinks around about 300 milligrams (mg) of caffeine daily. This is enough to hurt your blood sugar levels, spiking your insulin.
“One thing this hormone is very good at storing is fat in your midsection,” says Dr. Vincent M. Pedre. “Keeping insulin elevated can make your cells less sensitive to its ‘signal’; this is insulin resistance. To lose weight and keep it off, you want your cells to be the opposite—insulin sensitive.
Short-term disruptions in insulin sensitivity and blood glucose levels, which lead to weight gain in the form of increased abdominal fat, then deposit a feed-forward mechanism in your abdomen that propels the forces of weight gain, even as blood sugar levels may have normalized with long-term caffeine consumption.”
While the effects will be more dramatic if you chug seven cups of coffee, some people are affected by as little as two cups. It all depends on how quickly your body metabolizes caffeine. For slow metabolizers, the caffeine hangs out in their system for longer and is more likely to spike their blood sugar levels and cause health problems. Meanwhile, fast metabolizers can absorb the antioxidants more quickly without negative effects.
Then, there’s the fact that caffeine can put added pressure on your adrenal glands. When your adrenals are in overdrive, it floods your body with the stress hormone cortisol. When your body is in this ‘flight or fight mode,’ it can prevent your digestive system from working as it should and increase your appetite. It can also encourage your body to hold onto more belly fat long-term.
The good news is you don’t necessarily have to ditch your morning brew to shed or maintain your weight. It’s all about being smart about how you consume it. For most people, a good rule of thumb is to cap your consumption at one or two cups and never after 2 pm. You also want to pay attention to how you have your coffee—if you have it with full-fat milk and a spoonful of sugar, that’s not going to do you any favors regarding the calories.
You can take a DNA test to determine how sensitive you are to coffee and how quickly you metabolize it. If you’re a slow metabolizer, you may want to limit your consumption to one per day or cut it out completely. The same goes for if you’re going through a particularly stressful or chaotic time. The last thing you want to do is pump your body with caffeine when your adrenals are already working overtime—it will make you more anxious and may lead to weight gain. You may want to switch to mushroom coffee (which has calming adaptogens and blood sugar-stabilizing mushrooms) or one of these coffee alternatives.