News Flash: Calorie Burn, Keto Diets, and Exercise and Mood

Every week, we’re bringing you a roundup of the latest health and wellness news to hit the wire. This week, the latest on why how your body burns calories matters more than the number of calories burned, why the ketogenic diet may not be appropriate for athletes, and how even a small amount of exercise boosts mood.

All calorie burns aren’t created equal

Tracking calorie burn on your Fitbit is certainly one way to help maintain a healthy weight. But it’s not everything. Why? Different types of workouts have different effects in the body long after you leave the gym.

Your wearable device may measure the calorie expenditure during your workout, but it doesn’t accurately measure the metabolic after-effects specific to the type of movement you’re doing. When researchers at the Auckland Institute of Technology compared the physiological and hormonal responses in 12 healthy female participants to both cardio and resistance training workouts, there was a significant difference.

The resistance training—in this case, a Les Mills BODYPUMP class—triggered far greater fat-burning responses in the body than a cycling class of the same length. When the participants’ blood was taken after exercise to measure their hormonal profiles, levels of Human Growth Hormone (HGH), which oxidizes fat and builds lean muscle, was 56 percent greater after the resistance training compared with steady-state cycling. Furthermore, that lean muscle tissue burns more calories over time.

“Calories matter, but so does how they were burned,” said lead researcher Dr. Nigel Harris. “We now know the type of exercise used to burn those calories impacts the long-term, positive effects that exercise has on your body.”

Even moderate exercise burns extra calories throughout the day

But don’t ditch the cycling yet. Varying the type of exercise that you’re doing is healthy, and new research from the University of Alabama shows that even moderate aerobic exercise—not just high-intensity bouts as previously thought—boosts resting calorie burn throughout the day.

The research published in the journal Medicine & Science in Sports & Exercise evaluated 33 young women before and after 16 weeks of aerobic cycling training, carefully measuring their calorie consumption both during and for 23 hours after in a whole-room calorimeter. The investigators found that energy expenditure was elevated for at least 22 hours after moderate exercise (50 percent of peak heart rate) and high-intensity interval exercise (84 percent of peak), burning an additional 64 and 103 calories a day respectively for the two intensities, which may be explained in part by stimulation of fight or flight systems in the body, as well as repair of muscle damage.

Ketogenic diets reduced athlete’s performance

Your friends may be touting their ketogenic diet for weight loss. But can they keep up with you in the gym? A small study, conducted at Saint Louis University, examined the exercise performance of 16 men and women after following a low-carb ketogenic diet or a high-carbohydrate diet for four days.

The researchers found that those following the keto diet did not perform as well on the anaerobic exercise tasks given to them. For the average person, researchers said this could translate into a harder time climbing a flight of stairs. For athletes, however, it could mean impaired performance in high-intensity, short-duration exercise and sports.

It doesn’t take much movement to make you happier

People who work out just once or twice a week or for 10 minutes a day tend to be more cheerful than those who never work out, according to a new review of research of moods and physical activity in more than 500,000 people of all ages. The study was published by University of Michigan researchers in the Journal of Happiness Studies.

And the type of exercise doesn’t matter; it could be walking, weights or yoga. Those getting the American and European recommendation of 30 minutes a day were about 30 percent more likely to consider themselves happy, compared to people who did not meet that guideline. It’s not clear whether greater happiness is associated with feeling healthy, or if it actually causes changes to brain chemicals that promote a good mood.

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Photo credit: Jacob Ammentorp Lund, Thinkstock