By Fleur van Griensven
You might have heard the saying: ‘Carbs are bad for you’ or ‘eating after 8 pm makes you fat’. A lot of people claim that this will result in fat gain. Are carbs really the enemy or are these two examples just one of the thousand misconceptions in the fitness industry? Can we actually benefit from cycling our carb intake whilst cutting? Is carb cycling the secret to get shredded?
What is Carb cycling? Carb cycling is just what the name implies: Cycling the carbohydrate intake during the week, which translates into higher carb days and days with fewer/no carbohydrates. This is also called a non-linear dieting approach. A linear dieting approach means that the amount of calories and ratio of carbs/protein/fats remains the same every day. Thus, the non-linear dieting approach includes differences in the amount of calories, carbs, protein and fats between different days. I will try to make this clearer with an example.
If you would eat 200 g carbs, 150 g protein and 60 g fat 7 days a week you’d be following a linear dieting approach
If you would eat 250 g carbs, 150 g protein and 60 g fat on your 5 training days and 150 g carbs, 150 g protein and 60 g fat on your 2 rest days, you would be following a non-linear/carb-cycling diet.
With a carb-cycling diet, you basically manipulate your carbohydrate intake on different days of the week. Figuring out how much carbs to eat on these days is not that simple, but we will get back to that later on. In addition, I will give some tips on how to incorporate carb cycling in a diet yourself.
When can it be used and what are the benefits? Carb cycling can be used both during a cutting (caloric deficit) and bulking period (caloric surplus). In this article, we will not cover carb cycling during a bulk. Carb cycling can be used from the start of a cut or when you go deeper into a caloric deficit. Most people will choose the second option. They do this because as calories are decreased a lot, it’s harder to stay motivated. Having different amounts of calories on different days might give you something to look forward to.
Carb cycling may have some potential benefits. Firstly, for some it gives a psychological boost and motivation to keep going. Implementing higher carb days gives you something to look forward to when dieting gets tough. The prospect of a day filled with pasta, bread or whatever carb source you’re craving can just be enough to keep on track with dieting.
Menno Henselmans, the founder of Bayesian Bodybuilding, has been talking about carb cycling in one of his interviews. Bayesian Bodybuilding uses an evidence and scientific-based approach to bodybuilding, so everything is based on scientific data. In this interview, Menno Henselmans says that there are almost no studies done on the carb cycling approach and the physiological benefits. The science about carb cycling is lacking, which I also encountered when digging deeper into this topic. Menno Henselmans believes that the few days during which the carb intake is increased, or higher carb days in general, do not have any practical physiological effect. A few days of increased carb consumption after several days lower in carbs is not enough to bring hormones related to hunger and appetite back to normal. 
There are however some studies that looked at the effect of an increased carbs intake for one or more days on a hormone that are related to hunger and appetite.
One of these hormones is leptin. Leptin is a hormone secreted (produced) by fat cells and controls both long-term energy balance and appetite. When body fat is going down during a cut, leptin production is decreased over time. This results in more and more hunger when you are deeper into a cut. Here the fun part of shoving your face with carbs comes in. Higher carb days, also called refeed days, are thought to bring the lowered leptin concentration back to a normal level. This will reduce the increased sensation of hunger (for a while), which might help you to stick to your diet.
However, recent studies did not show that a refeed or just one-high carb day can bring leptin levels back up. Yes, refeeding does give a rise in serum leptin levels, but leptin levels return to baseline (the starting point) after 24h. This means that leptin levels are not restored long-term. Switching between higher and lower carbs days is not going to do much for an improvement in leptin and thus those hunger feelings will still be there. 
Carbs are the main energy source during physical activity, because they provide the glucose that is required for energy. What most people experience is that eating more carbs will result in more energy during their training session. This results in them being able to train harder and lift more. That’s why it is recommended to have higher carbs on the heaviest training days.
How to set up your carb cycling plan?  The most crucial thing in setting up macros for a carb cycling diet is to still have the same weekly total carb intake as you would have in a linear dieting approach. We leave aside protein and fat for the moment as they remain the same and we are only going to manipulate our carb intake on different days. Let’s go back to the example used earlier to show how you can set it up yourself.
On a linear diet, we would have 200 g carbs x 7 days = 1400 g of carbs per week.
For example, on a carb cycling diet it could look like this:
190 g 6 days per week and 260 g 1 day per week.
184 g 5 days per week and 240 g 2 days per week.
185 g 4 days per week and 220 g 3 days per week.
How you choose to set up your carb cycling plan is all personal preference. A few factors you can take into account are:
How often do you train? If you only train two or three days a week, bigger carb load days might be more beneficial for you. If you instead train five or even six days a week, a more moderate spreading of carbs might be better.
What are your heaviest training days? If adding more calories on these days gives performance a huge boost, go ahead and train the house down.
What suits my lifestyle? Can you be a bit strict during the week and have more carbs to spend for burgers with friends during the weekend? Or would you rather have a more moderate carb intake?
Conclusion, Carb cycling: The secret to get shredded? NO carb cycling is not the secret to get shredded. The secret to get lean is maintaining a caloric deficit for as long as needed to achieve the physique or shape you’re after. If cycling your carb intake (in whatever way you choose to do so) makes it easier to stick to your diet, carb cycling might be a good strategy. Alternatively, if you enjoy doing it and get results from it, then do it. However, keep in mind that it won’t give you better results than a linear-dieting approach with a daily constant caloric deficit. Whether you use a linear or non-linear dieting approach like for example carb cycling does not matter as long as your weekly caloric averages come out the same.
Take home message: Don’t overcomplicate the whole fat loss thing, it’s not rocket science. Stick to a caloric deficit, choose a strategy you can do consistent and rock the beach this summer!
References:  Henselmans, M. (Bayesian Bodybuilding). (2015, 24 February). Refeeds, Body Recomposition & Non-Linear Diets. [Radio Podcast]. In Danny Lennon. Sigma Nutrition& Performance.
 Kolaczynski J, (1996). Responses of leptin to short-term fasting and refeeding in humans: a link with ketogenesis but not ketones themselves. Diabetes. 45(11):1511-5.
 Cheadle, N (2015, 13 November). Carb cycling for fat loss. Retrieved from https://www.nickcheadlefitness.com/carb-cycling-for-fat-loss/ on April 26th 2017