Wellness Wednesday: What's the Deal With Carb Cycling?



Carbohydrate intake has been a hotly contested topic in the fitness world for a number of years. Some diets advocate a low-carb or even no-carb approach; while others place more emphasis on quality of nutrients and overall calorie intake. While no macronutrient is inherently bad, carb intake can definitely be viewed as a macronutrient whose intake needs to be tailored to the eater’s specific needs. Enter the concept of carb cycling. Carb cycling can best be described as changing total carbohydrate intake levels into days of high or moderate and low carbohydrate intake. Level of intake can be adjusted based on variables such as:


Body Composition/ Weight Loss Goals:  low carb days are often programmed during a weight loss phase and may be elevated in times where muscle/ strength gain is the main goal.


Training vs. Rest Days: another popular way of modifying carb intake is to coordinate your high carb days with the days that you are also training heavily, saving your low carb days for rest days, when you theoretically will need less energy overall.


Training Intensity/ Modality: some athletes further break down carb intake based on intensity and type of training- high intensity, long duration or increased cardiovascular output equal moderate or high carb days whereas lowering the intensity and/ or duration mean low carb.


Competitions/ Races:  Some endurance athletes will also “carb load” before an event, in an attempt to pack their muscles (and liver) as full of glycogen as possible to fuel prolonged exertion.


How-to: Choose your own adventure. A typical week will include a couple of days of low-carb, a couple of medium-carb days and a day or two of high carb. Protein intake is usually similar between phases. Vary your fat in the opposite direction as your carbs. High carb = low fat. Low carb? Dial up your fat to make it to your calories and hold your protein steady.


What Science Says: Carb cycling tries to match your body’s need for carbs on a daily basis- like providing more carbs around your workouts or times of intense training. High carb days are also important because they replenish the stored energy in your muscles. This is thought to improve performance and reduce the potential for muscle breakdown.


Although science is anything but a fixed science, the mechanisms behind carb cycling seem to suggest that it may be an effective means to weight loss, if applied correctly. How? Like any weight loss diet, carb cycling creates a calorie deficit. Carb cycling is also thought to increase insulin sensitivity, which is not only tied to weight loss but is also a marker of overall health. Low carb days also may have a positive effect on hormones related to fullness. However, like many things in the science of nutrition, opinions differ on the subject and more research is needed.


Want to know more? Here are some research articles dealing with the subject.


1.     Glycogen resynthesis after exercise: effect of carbohydrate intake



2.     Coingestion of carbohydrate with protein does not further augment post-exercise muscle protein synthesis



3.     A lower carbohydrate, higher fat diet reduces abdominal and intermuscular fat and increases insulin sensitivity in adults at risk of type 2 diabetes