You just went for a run. How many kilojoules did you blast? Chances are, your guess outpaces reality, to the tune of, say, a Frappuccino. Overestimating kilojoule burn is the Big Daddy of runners’ weight-loss mistakes, says Lisa Ellis, a well-known nutritionist.
But it’s not the only misstep. Sneaky slipups can derail the weight-loss efforts of even health-savvy runners.
Here’s how to avoid these eight common mistakes:
1. Miscounting Kilojoules
It’s true that running eats up more kJ’s than nearly any other activity: The average man burns 520 kJ’s per 1.5km and the average woman burns 440 kJ’s, which means a 5km nets you a 1317- to 1556-kilojoule deficit. But you can easily overspend your kilojoule deficit with something as simple as a flavoured latte and a chocolate-chip cookie.
Correction: Get a better estimate of your kilojoule burn with an online calculator or with a GPS watch that allows you to input your height, weight, and other stats. If you’re prone to overindulging post run, avoid blowing your kilojoule deficit by finding a couple “reward” foods with easily controllable portions, like bite-size cookies or single-serving chips.
2. Skimping on Fat
Feeling good with your dry toast, naked salads, and splash of watery skim milk in your coffee? Not so fast: Your body needs fat to absorb vitamins like A, D, E, and K, and to regulate hunger; fats are digested more slowly than carbs and protein, keeping hunger at bay longer. It’s also believed that fat helps your body sense the appetite-regulating hormones ghrelin and leptin, says Ellis. A no-fat or very-low-fat diet leaves those hormones in disarray.
Correction: Fat should make up 20 to 30 percent of your daily kilojoules. But avoid trans fats (in processed foods) and limit saturated fats (meat, dairy). Rely on mono- and polyunsaturated fats (olive oil, nuts, seeds, avocados, fish); these protect your heart and promote satisfaction. A recent study found that even the aroma of some fats, particularly olive oil, may prompt the release of satisfying hormones.
3. Running on Empty
You may have heard this one: Hit the road without breakfast and your body will burn fat. But it doesn’t work the way you’d hope. Rather than seeking out fat immediately, your muscles first use carbs that have been stored in your muscles as glycogen, says Rachel Berman, R.D. When those stored carbs run out and your body starts to burn fat, your energy plummets, forcing you to slow down and burn fewer kilojoules than if you had properly fuelled up.
Correction: If you’re heading out for 30 minutes or less on an easy run, you can skip a pre-runsnack, since you probably have enough glycogen to power you. But if you run longer or harder, you should have a 420- to 840-kilojoule snack about an hour before your run. Choose carbs and a bit of protein, such as a banana with peanut butter, and drink water to hydrate.
4. Not Fueling Postrun
After longer or tougher workouts, your muscles have gobbled up all the glycogen they needed, and now they’re hungry. Thing is, you might not be; many runners find their appetite is suppressed just after working out. “But later, when your body settles in and ‘realises’ its glycogen stores are low, you’ll feel much hungrier,” says Berman, leaving you prone to inhaling everything in sight.
Correction: Aim to refuel within an hour of tougher workouts to re-power your muscles and stave off hunger later. The American College of Sports Medicine recommends a 4-to-1 ratio of carbs to protein. Keep this snack to fewer than 840 kilojoules. With 670 kilojoules per cup, low-fat chocolate milk fits the bill nicely, providing the ideal mix of carbs and protein.
5. Running Gel Overdose
Addicted to mid-run refuelling? You may be piling on more kilojoules than you need by overdependence on energy bars, gels, drinks, and shakes. “Kilojoules from mid-race fuels are dense, add up quickly, and usually don’t do much to suppress hunger,” says Berman.
Correction: For runs shorter than 60 minutes, skip the gels and sports drinks; water is fine. Go longer and you should consume 30 to 60 grams of carbs (one or two energy gels or 473ml to 946ml of sports drink) per hour of exercise.
6. Drowning in Kilojoules
Kilojoules in a cup, count just as much as those on your plate. Alcohol is particularly sneaky: Add in sweetened beverages like coffee, tea, fizzy drinks, and juice, and you could be overdoing it big-time. Studies show that, in general, liquid carbs don’t contribute to satiety the way solids do. That means if you down 840 kilojoules at the bar, you won’t compensate by eating 840 fewer kilojoules at dinner.
Correction: Most of the liquid you drink should be kJ-free like water or unsweetened tea. Remember that alcohol may trigger overeating as your inhibitions drop. “Moderate drinking means one a day for women, two for men,” says Berman. “Cut kilojoules by choosing light beer, wine, or liquor mixed with sparking water. Avoid frozen drinks, which are high in sugar.”
7. Rushing Results
Blame overblown weight-loss expectations on celeb-endorsed juice cleanses or reality shows like The Biggest Loser. But trying to change everything at once or reaching for TV-ready results is often overwhelming enough to cause you to abandon your weight-loss plan, says Berman. If you are dropping a kilo or two per week, that’s a sustainable pace, she says.
Correction: Make small changes, one at a time. Try to eat a healthy breakfast every day, for example. Swap out chips for an apple at lunch. It’s not sexy, but it works. Rather than zeroing in on the scale, reward yourself with a manicure or piece of gear as changes morph into habits.
8. Not Re-evaluating
It’s a physiological fact: Bigger bodies burn more kilojoules, even at rest. That’s why the more you have to lose, the quicker you’ll see weight-loss results. But as you shed kilo’s, your body adjusts and, frustratingly, burns fewer kJ’s (including while running). So what worked initially, will need to be tweaked as you slim down.
Correction: Every time you lose 10 to 15 percent of your weight, re-adjust your daily kilojoule intake, says Berman. Find your new (smaller) needs here. Re-calculate your exercise burn, too, since that also decreases as you slim down.