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Medically Clear

Brew and Burn?

Ballard, Dustin MD

doi: 10.1097/01.EEM.0000472782.93040.62
Medically Clear

Dr. Ballardis an emergency physician at San Rafael Kaiser and the medical director for Marin County Emergency Medical Services in San Rafael, CA.





Are you looking to liquidate some pounds? Discard a dollop of dumpiness? Evict the extra paunch? You are not alone. Halloween is just around the corner, after all, and that minion costume is not going to fit itself!

All sorts of tummy-trimming options are out there, and some are healthier than others. You can go low carb or turn paleo (but not gluten-free; that can actually pack on the pounds). You could dial up a fitness fad like P90X or CrossFit (but go easy; don't get hurt!), or drop dough on a plastic surgery solution. For those with weight loss on the mind, you may not realize that you probably have an unlikely fat burning ally at home in your kitchen (and, no, I'm not talking about the padlock on the snack cabinet).

Turn your attention please to the world's foremost wakey juice, that dark delicious dirt we know as coffee. That's right. The ticket to a safe fitness fast-forward might just include your morning caffeinating ritual.

Ninety percent of the world's adult population drinks caffeinated beverages daily, and recent literature supports a manifold of health benefits linked to regular coffee intake because of its caffeine content and its cocktail of antioxidants. Drink two to three cups of coffee each day and you may have better blood sugar and an approximately 10 percent lower risk of dying from any cause. It's no secret that caffeine promotes alertness, which is beneficial at the workplace (like I need to tell you that!) and in athletics. In fact, the International Olympic Committee deems caffeine a performance-enhancing drug, and imposes limits on how much of it can be present in athletes' urine.

Add to this accumulating list of commendations a study suggesting that drinking caffeinated coffee prior to moderate interval exercise (exercise that is sprinkled with periods of rest and then repeated) can promote fat-burning.

Researchers from Osaka, Japan, performed precise physiologic testing in seven healthy adult male volunteers. (Clin Physiol Funct Imaging 2015 July 17; The participants drank instant coffee or hot water before doing three 10-minute bouts of exercise (each separated by a period of rest) or a single 30-minute session of exercise. All exercise was performed on an ergometer exercise bike at moderate effort (40% of full effort.) The amount of coffee consumed was determined by body weight — 5 milligrams per kilogram — and in an average-sized person, that equates to two strong cups of coffee.

The researchers measured and compared components in the exhaled breaths of the volunteers and determined the relative percentages of the types of fuel (fats versus carbohydrates) participants were oxidizing before, during, and soon after exercise. They found increased fat oxidation after exercise when people drank pre-workout coffee compared with hot water. Fat oxidation levels were also moderately increased 30 minutes post workout in those who did interval training versus a single exercise session.

We should note that this was a small study that was restricted to measuring short-term effects. Certainly more research would be useful to see how this might hold up over time (does the body adapt over time to burn less fat after coffee?) and in other age and gender groups.

It should be noted that the results seen in this study were rather modest. This brew-and-interval-burn approach is unlikely to show dramatic and immediate results. Rather, it might just be a lifestyle choice that contributes to longer health benefits. The results of a large genomic study of 120,000 coffee drinkers of European or African ancestry published earlier are instructive. Researchers from the Harvard T.H. Chan School of Public Health found six specific genetic variants in regular coffee drinkers, two that deal specifically with caffeine metabolism. (Mol Psychiatry 2015;20[5]:647.) This is good evidence that, like with other substances such as alcohol, people have genetic predilections toward tolerance and metabolism.

The investigators also found two genes involved in glucose and lipid metabolism that are linked to the metabolic and neurologic effects of caffeine. This finding suggests a genetic explanation that drinking coffee before exercise can accelerate fat oxidation. Also consider that previous research investigating caffeine and more intense exercise has demonstrated increased energy expenditure and fat oxidation with a pre-workout caffeine boost.

But before we all go all in on the brew-and-burn approach, we should quickly mention the (inevitable) caveats. Coffee, and caffeine in particular, can have some serious side effects, and not just the fallout of the 3 a.m. Starbucks run in Las Vegas or the acrid night shift gastritis after one too many mugs. Aside from the well-known side effects — palpitations, tremors, temporary hypertension — be aware as well of the possible association with lower bone mineral density and increased fracture risk in older women.

Moderation is advised, and I suspect that not everyone's vision of safe weight loss is going to be a coffee shop outfitted with treadmill desks. But come to think of it, a busy ED shift is not unlike a caffeinated treadmill workout; we already brew and burn. Just one more advantage of our specialty.

You can learn more about this topic by listening to the Medically Clear podcast on iTunes or on Dr. Ballard's website,

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