Here's The Best Time Of Day To Work Out To Lose Weight
New research, recently covered by Gretchen Reynolds in The New York Times, suggests that working out early in the morning - before you've eaten breakfast - helps speed weight loss and boost energy levels by priming the body for an all-day fat burn.
The No-Snooze Payoff
One of the reasons working out first thing in the morning appears to help us lose weight - or at least protect us from gaining it - is that it pushes the body to tap into its fat reserves for fuel, as opposed to simply "burning off" our most recent snack or meal.
In one recent study, 28 young, healthy men spent 6 weeks eating a hefty diet of 30% more calories and 50% more fat than they'd been eating before. But while some of them spent the 6 weeks stuffing themselves and barely exercising, the others started working out every day. Of those who worked out, half did so first thing in the morning; the other half hit the gym (and did the exact same workout) after a high-carb breakfast. (The fasting exercisers ate the exact same breakfast, they just did so after working out.)
At the end of the volunteers' month-and-a-half-long eating fest, the ones who hadn't worked out at all had (unsurprisingly) packed on the pounds - about 6 each, to be exact. The ones who'd been exercising after breakfast gained weight too, but only about half as much.
In comparison, however, the people who'd worked out daily - so long as they hit the gym before breakfast - hadn't gained any weight at all. They'd been able to eat a lot of extra food - just as much as their fellow volunteers - without paying the price in additional pounds.
The study was small, short-term, used a very specific eating plan, and only involved men around the age of 21, so it's hard to extrapolate too much from the results. And the fasting exercisers didn't actually lose weight - they just didn't gain weight. Still, the experiment provided some of the first evidence that "early morning exercise in the fasted state is more potent than an identical amount of exercise in the fed state," the authors write.
Another smaller study helps point out why timing could be so important. In it, two groups of men ran on treadmills until they burned 400 calories (about the equivalent of a small meal or about 3-4 slices of toast). While one group ran on an empty stomach, the other ate a 400-calorie oatmeal breakfast about an hour before their workout.
All of the runners burned fat during their workouts, and remained in a heightened fat-burning state after they'd gotten off their treadmills. But both results were more intense for the runners who'd skipped the oatmeal. In other words, exercising after a long period of not eating could be setting us up for a longer, more intense fat burn.
Set Your Clocks
There's another component of the early morning workout regimen that can help with weight loss, too: daylight.
Aligning our internal clocks, or circadian rhythms, with the natural world helps give our metabolisms a boost. One recent study showed that people who basked in bright sunlight within two hours after waking tended to be thinner and better able to manage their weight than people who didn't get any natural light, regardless of what they ate throughout the day.
So next time you think about hitting snooze, remember this: an early-morning workout won't just help you meet your fitness goals, but could even give you more energy than those few extra minutes of shuteye.