“Carb cycling” adds a new spin to a lowcarb diet
Lowcarb diets continue to be popular for weight loss, with the keto diet being the latest craze. But these diets can result in low energy levels and headaches, and research has generated conflicting results on their longterm safety. One recent study of almost 25,000 U.S. residents found a 32 percent higher risk of premature death among participants who ate a lowcarb diet.
The negative side effects and growing concerns about the safety of lowcarb eating have left some dieters searching for a more middleoftheroad approach to consuming carbohydrates.
Enter carb cycling. Carb cycling is a nutrition strategy in which you alter the amount of carbo hydrates you eat on a daily, weekly or monthly basis to maximize sports performance and to build muscle and lose fat and weight. This approach has been practiced for years by bodybuilders and elite athletes in sports where body weight has an impact. It’s only lately that, because of our societal obsession with carbs, the approach has spread to the general public, showing up in mainstream health and fitness publications and as a hashtag in more than 350,000 Instagram posts.
Compared with lowcarb dieting, the theory goes, carb cycling could put your body under less stress, allow you to enjoy more flexibility in your diet and enable you to take advantage of the physiological perks that come from carbohydraterich foods, such as the benefits of fiber.
Carb cycling is still theoretical because it’s mostly based on research on the effects of either lowcarb diets or periods of highcarb consumption (“carb loading”) on athletes — not on alternating between the two. But here are some of the reasons athletes believe adding some highercarb days to a lowcarb diet could be beneficial.
On any diet, restricting calories causes your metabolic rate to slow down and affects hormone levels, which make you hungrier, making weight regain more likely. Research shows that carb loading can temporarily raise metabolism and increase levels of leptin, a hormone that blunts hunger, which, together, could help promote weight loss.
Research has also shown that carbohydraterich foods boost athletic performance and recovery, and that carbohydrates burned for energy spare protein, which then can be used for muscle growth rather than for fuel. Thus, the thinking goes, highercarb days once in awhile can help even nonathletes prevent a metabolic slowdown, enhance the effectiveness of their workouts, trim fat and build muscle. And lowercarb days the rest of the time can encourage the body to burn fat for fuel.
(As a side note, although there is some evidence that lowcarb diets promote weight loss in the short term, a Harvard study of 811 overweight adults found that whether participants were assigned a lower, medium or highercarb diet, there was no significant difference in weight loss after two years. So, although lowcarb diets seem to help some people lose weight, highercarb diets can work just as well when calories are reduced.)
But, as noted above, we don’t have research studies on carb cycling to tell us whether these diets are effective, much less safe over the long term. Another drawback is that they aren’t that easy to implement: Carb cycling takes plenty of math, meal prepping and weighing, and even more patience and experimentation. There isn’t a proven formula.
Anyone who wants to try carb cycling should talk to their doctor first, and meet with a registered dietitian to ensure they are meeting their energy and nutrient needs — and to help with the mindboggling calculations that need to be done first. But here are some general guidelines.
First, calculate your energy needs to know how many calories to aim for each day. You can get a rough estimate by multiplying your weight in pounds by 10 for weight loss, by 12 to maintain your weight and by 15 to gain weight. On highercarb days, you would try to get about half of your calories from carbohydrates, and on lowercarb days, you would try to get about 25 percent of your calories from carbs.
You would aim to consume one gram of protein per pound of body weight, and make up the rest of your calorie budget from fat. (Each gram of fat is