This article is for educational purposes only. Consult a nutritionist or physician before changing your dietary plan.
Simply put, carb cycling is an advanced diet that involves planned high-carb and low-carb days. Because a gram of carbohydrate accounts for four calories, this diet also involves calorie cycling (consuming more calories on some days than other days). The main goal of this type of diet is to lose fat while retaining muscle.
In addition, cycling carbohydrates mitigates the hormonal changes typical of most low-carb diets, such as increased cortisol (the body's stress hormone). Also, compared to ketogenic diets or the Atkin's diet, carb cycling can be easier to follow (you get to pig-out on carbs sometimes) and promotes a fast metabolism.
Math and Food Tracking
One of the most important parts of any diet is overall calorie consumption. If you consume more calories than your body requires, you will gain weight, and if you consume less calories, you'll lose weight.
To calculate caloric requirements, you first determine your basal metabolic rate (BMR), or how much energy your body would expend in a comatose state, and multiply by an activity level constant (more active people require more calories). This can be done using the Harris-Benedict Equation or the more accurate Katch-McArdle Formula if you know your body fat percentage.
However, a simpler and more practical way to determine your daily caloric maintenance level is to meticulously track your food intake using MyFitnessPal or JoyApp on your smartphone and a food scale, and then track your progress the first couple weeks using pictures and the scale, adjusting either way if losing too much weight or not enough. Moreover, fluctuations in hormones, sleep schedule and quality, as well as daily activity, can cause your body’s caloric needs to change dramatically, so there’s error either way.
Here are some typical macros for moderately active men (175 lbs with 15% bodyfat) and women (125 lbs with 20% bodyfat). Per pound of body weight for males: Protein = 1.5g (low day) - 1g (high day). Fat = 0.5g (low day) - 0.2g (high day). Carbs = 0.75g (low) - 3g (high).
For females, Protein = 1.1g (low day) - 0.9g (high day). Fat = 0.5g. Carbs = 0.8g (low) - 2.5g (high).
For a goal of fat loss, aim for 1-2 high days per week; for maintenance, aim for 2-3 high days; and for muscle gain, aim for 3-4 high days, with moderate and low days taking up the remaining days.
How to Actually Follow the Diet
The high-carb days combat this problem by keeping the hormones in check and encouraging muscle gain, since a response to insulin speeds the process of muscle recovery. Also, you should consume the limited amount of carbs on the low-carb days in the morning and after your workout, while on high-carb days, carbs should be consumed every meal.
What to Eat
Including these foods in your diet will not only make you more satisfied with each meal, but also fulfill your micronutrient (vitamins/minerals) needs. Buying food in bulk and preparing it in bulk will save money and time each week: you can put the leftovers in containers which can easily be reheated in minutes.
Overall, carb cycling is an advanced dieting technique that can allow you to gain muscle without gaining too much body fat or to lose body fat without losing too much muscle. This is done by eating a high amount of carbs (from grains and vegetables) on the most intense workout days, while eating a low amount of carbs on non-workout days. The frequent re-feeds offer many advantages over ketogenic diets (low-carb, high fat and protein) especially in keeping hormone levels appropriate, which is crucial for improving body composition.
For more information, check out Precision Nutrition and T-Nation. Also read Why You Seriously Need to Ditch the Low-Carb Diet Fad, what happens when A Spoon writer tries the keto diet for a week, and some tasty low-carb dishes.