Carb Cycling for Weight Loss: Does It Work?

by Kristen Domonell

We all remember the low-carb diet craze, which demonized carbohydrates in favor of high protein intake. Atkins-like diets helped people shed weight quickly, but were far from perfect. Some research suggested lower-carb diets could increase the risk of heart disease, and dieters often gained the weight right back after reintroducing carbs.

Now, carb cycling, a diet that alternates between high and low carb days, promises similar results, without depriving the body of any macronutrients. But can you have your cake and eat it too?

The Skinny

Believe it or not, the concept of carb cycling actually came from the bodybuilding industry, says personal trainer Heidi Powell, of ABC’s Extreme Weight Loss. They would bulk up while building muscle, then carb cycle to reduce their final layer of fat. Trainers caught on, and experimented to see if everyday people could manipulate their carb intake and get similar results.

After seeing how well it seemed to work, Powell started putting all her weight loss clients on carb cycling programs. She says they see dramatic changes as a result of the diet combined with exercise. Some research backs it too, including one British study that found that women who eliminated carbohydrate-rich foods twice a week (and ate their normal diet the rest of the time) lost an average of nine pounds over four months. Women on a 1,500-calorie Mediterranean diet, on the other hand, lost only five pounds in that time.

When a person pulls carbs from their diet for an extended period of time, they lose fat as well as a lot of water weight, explains Powell. But the longer they deprive themselves of carbs, the more they decrease their metabolism. Reintroducing carbs causes the body to rebound, holding onto every bit of carbs, sugar and water it can.

With carb cycling, the body is never deprived of carbs long enough to slow the metabolism, and is able to get into a catabolic fat burning state on the low carb days. Essentially, the high carb days act as “boost” days, increasing metabolism, and the low carb days act as “burn” days, when the body is an optimal state to burn fat.

The Plan

The goal of carb cycling is to consume the most amount of carbohydrates possible while still making progress towards your goal, says Roger Lawson, C.S.C.S., a trainer at All-Access Fitness Academy in Shrewsbury, MA. The more intense a workout, the more carbohydrates will need to be ingested to fuel a session. But there’s a fine line between fueling up and impeding progress.

The “Classic Cycle,” a straightforward plan designed by Powell’s husband Chris (and featured in his book Choose to Lose: The 7-Day Carb Cycle Solution), alternates between low-carb and high-carb days, with the seventh day as a reward day. On the reward day, you can eat foods that may have been off-limits on other days. Psychologically speaking, Powell says including rewards is part of what makes some people so successful on the plan. “It helps them mentally and emotionally feel like they’re never deprived of foods they can’t have on a typical diet,” she says.

On this and other cycles, individuals will feel results in about a week, and start to see them in two weeks, says Powell. She recommends a 12-week cycle for the best physical and mental results, but says the principles of carb cycling can be followed for any phase of life, including weight loss, maintenance, fitness and performance.

The Fine Print

While no specific types of carbs are technically off-limits, the carbs should ideally come from unprocessed, whole foods such as rice, oats, potatoes, whole grains and breads, Lawson says.

Unlike their sugary counterparts, research suggests that healthy starches (or resistant starches) like grains, beans and legumes can help with weight loss by boosting metabolism. In one Australian study, rats that ate a diet low in resistant starch gained fat and lost muscle mass, while those that ate a diet higher in resistant starch preserved their muscle mass despite the higher carb intake. (Though, it’s not 100 percent clear whether the same holds true for humans.)

Another important thing to keep in mind is that carb cycling shouldn’t be a carb or junk food free-for-all, proponents advise. “But don’t fear bringing the occasional treat into the mix either, as long as is total carbohydrates are accounted for,” Lawson says.

The Takeaway

Like any dietary strategy, carb cycling isn’t for everyone. And with the most current research having been done on mice, it might be a while before carb cycling can be recommended as a science-backed weight loss technique. But for healthy individuals willing and able to adjust their carb consumption according to fairly regimented guidelines, some experts suggest carb cycling can lead to positive body composition changes while still letting you enjoy dessert and a glass of wine from time to time.

Comments:
Carb cycling mainly works by optimising insulin secretion - to produce it in abundance when you need it and minimise it when you don't. But to strip away fat there needs to be a calorie deficit it is not just moving carbs from 1 day to another. When weight training as you add carbs it creates powerful anabolic conditions to grow and repair muscle. (Muscles seem to recover faster when there are carbs available. Body builders were fast to pick up on the benefits because they needed to grow muscle and strip away fat.) Low carb days need to be lower calorie days where you are still exercising but don't necessarily need to weight train.

(There is always an equilibrium in the body depending on the nutrients it receives and the hormones that are present. Having the right hormone composition is a massive aid in losing weight and preserving muscle. For myself and people reading this blog it is very likely you have not been able to just rely on hormone composition - but have optimised it so much already. We all know people who can coast on their genetics to keep them slim but that is not us.)

Low insulin conditions can aid with growth hormone and testosterone release which helps to remove fat. Hard bursts of exercise are also very good for aiding the release of growth hormone, testosterone and triggers fat burning for much longer post workout.

If you want to carb cycle start by timing your carbs for after workouts and relying less on them when you are less active. The nature of the carbs is best for whole carbs so you get the benefits of the other macro and micronutrients as well. (Sugar by itself is very deficient in nutrients and requires other food to provide the assisting nutrients to metabolise it. So pure sugar is just a source of fuel without any other nutrients. Although sugar is a powerful activator of insulin, if you really must have it then a better time is after a hard work out rather then when you are not active (eg sitting at a desk and not needing a boost of insulin)).

Very low carb, low protein result in a state of ketosis but it is not ideal if you really like a wide range of carbs. Carb cycling can allow you to compromise between a large range and larger amount of carbs. This also allows for a larger range of recipes which can make it far more suitable as a longer term strategy to keep fat low. I prefer this to full ketosis.