Carb Cycling & the Power of High/Low Days
When trying to lose or maintain weight a lot of people think they need to chop down their carbs — or eliminate them completely.
But this restriction cuts out so many of the great-tasting parts of life, from pizza to pineapple. That’s why a long-term, low-carb diet can be incredibly taxing on your mind and body and many find it difficult to maintain. And, in a world where adherence is the key to diet-success, ditching carbs completely can be a recipe for failure.
But is carb cycling — a diet that bodybuilders, athletes, and everyday people have been using for years — the answer? Let’s find out!
Carb Refresher
Carbs are one of the three macronutrients and our body’s main source of fuel. Every cell in your body is capable of using glucose (the broken-down form of dietary carbs) for energy. They’re important for proper muscular, cardiac, kidney, and brain function and they keep us going through tough workouts. Think of your body like a car and carbs as the gasoline. Just like a gas tank, you can’t go anywhere without fuel, but you don’t want to overfill either. That’s why carb cycling (instead of the “boom or bust” mentality of low-carb diets) is so appealing.
Carb-Cycling Basics: We’re Not Talking Bicycles
Put simply, carb cycling is a planned change in carb intake from day to day. Essentially, you split your week between high-carb, low-carb, and sometimes no-carb days. As long as the weekly average calories (take all the calories for each day of the week and divide by 7) put you in a deficit, then you can see the same progress with carb cycling as you would with any other diet.
A typical “high day” might be 1–1.5 grams of carbs per pound of bodyweight, while a “low day” of carb cycling might be half that or less. In the Avatar system, you can set these up in the High/Low Days setting, which will let you choose the difference between high- and low-carb days. Then, the amounts will be tweaked as you go based on your results, activity level, and preferences.
In any case — whether you’re using Avatar or not — your fat and protein intake will (mostly) remain the same throughout. Both are essential for building muscle and maintaining a healthy body. Because these are kept relatively consistent while your carbs change, your calories will cycle too. The goal, however, is to burn more calories than you eat over the span of a week — without restricting every single day and losing your mind.
When carb cycling, the most common schedule is to eat low carb for 3–4 days followed by high-carb for 2–3 days. But you don’t have to follow a set schedule. The point of carb cycling is to have the freedom to eat more or less on certain days. So, if it makes sense to schedule your high days on the weekends, go for it. If you need four high days each week to stay sane, or you’d like to experiment with adding just one — it all works. Just make sure you’re in an average weekly calorie deficit and you’re good to go!
Carb cycling isn’t for everyone, though. It can be tricky for beginners who are new to tracking macros. But, as we’ll see, there are some big advantages to “undulating” your carb intake day to day. Let’s keep learning!
Why Not Just Eat Low-Carb?
Sure, low-carb diets like Atkins and keto work really well for lots of people, but they’re very difficult to stick to and people burn out quickly. On top of that, studies have shown that there’s no statistical difference in weight loss when on a low-carb versus a low-fat diet, as long as calorie intake is the same [1,6]. (One more time for good measure: Carbs are not the enemy!)
Our bodies can function relatively well without carbs, and decently well without calories for short bouts of time.
Some evidence even suggests that short and infrequent episodes of fasting (like briefly dropping carbs) may have health advantages, such as improved markers of cardiovascular disease [2].
However, when the body goes hungry for too long it goes into “starvation mode” and metabolic damage can occur. Studies also show that continuous calorie restriction (like long-term dieting) is linked to slower metabolism [3]. That means that as you eat less food you burn fewer calories. This is where the intermittent plan of carb cycling can be really helpful. More on that in the next section.
How It Really Works
Lower-carb, higher-protein diets have beneficial effects on fat loss, cholesterol, and lipid levels [4]. With carb cycling, the idea is to take advantage of the benefits of reducing carbs (and calories) on the “low days” to blast fat without burning much muscle or incurring the long-term damage to your metabolism that endless low-calorie days can do.
Then, during the ”high days” (when you eat more carbs), your body burns more calories and increases leptin secretion (a hormone that keeps you from being hungry) [5]. These two side effects will keep your metabolism running and help prevent you from overeating. The higher-calorie days can also help a diet seem less monotonous and more bearable. Since you’re free to eat more food on the high days, you won’t struggle as much with “life” (aka office parties, nights out, etc.). This benefit works both practically and psychologically. Plus, high-carb days can be paired with your harder exercise sessions, fueling better workouts and spurring better progress!
By repeating this cycle over and over, you’re able to burn fat, build or maintain muscle, and hopefully prevent plateaus. Again, there’s nothing magical happening here. It’s just a fancier (and more fun) way to get into a calorie deficit while still eating a decent amount of food some days each week.
That means that a high day is not a “cheat day” or a “diet break.” You still need to pay attention to your macros, stay in a deficit, and stick to the plan. The plan gives you more freedom, but it’s not a free-for-all!
Back to Basics
Carb cycling can work, and if you love it — great! However, for most people, losing weight comes down to one simple thing: burning more calories than you eat [6,7]. Whether you’re extremely active, a professional athlete, or a stay-at-home parent, eating more energy than you burn will make you gain weight. So, if carb cycling doesn’t tick that box (keeping your calories where they need to be on average) it’s not going to work for you, no matter how awesome that extra slice of pineapple pizza would be.
But with the right plan and personalized macros, carb cycling can tune your diet to your body, your schedule, and your needs. That sounds like a recipe for success!
References
1. Gardner C., Trepanowski J., Del Gobbo L, et al. Effect of Low-Fat vs Low-Carbohydrate Diet on 12-Month Weight Loss in Overweight Adults and the Association with Genotype Pattern or Insulin Secretion. JAMA, 2018; 319(7) 667–679.
2. Benjamin H., Heidi M., Jeffrey A., et al. Usefulness of Routine Periodic Fasting to Lower Risk of Coronary Artery Disease in Patients Undergoing Coronary Angiography. The American Journal of Cardiology, 2018; 102(7) 814–819.
3. Muller M., Enderle J., Pourhassan M., et al., Metabolic adaptation to caloric restriction and subsequent refeeding: the Minnesota Starvation Experiment revisted. The American Journal of Clinical Nutrition, 2015 September; 102(4) 807–819.
4. Parker B., Noakes M., Clifton P. Effect of a high-protein, high-monosaturated fat weight loss diet on glycemic control and lipid levels in type 2 diabetes. Diabetes Care; 2002 March; 25(3): 425–430.
5. Dirlewagner M., Guenat E., Di Vetta V., et al., Effects of short-term carbohydrate or fat overfeeding on energy expenditure and plasma leptin concentrations in healthy female subjects. International Journal of Obesity, 2000 December; 24(11): 1413–8.
6. Aragon AA, Schoenfeld BJ, Wildman R, et al. International society of sports nutrition position stand: diets and body composition. J Int Soc Sport Nutr (2017). 14:16.
7. Das K., Roberts S., Bhapkar M., et al. Body-composition changes in the Comprehensive Assessment of Long-Term effects of Reducing Intake of Energy (CALERIE)-2 study: a 2-y randomized controlled trial of calorie restriction in nonobese humans. The American Journal of Clinical Nutrition, 2017 April; 105(4) 913–927.
8. Jensen M., Ryan D., Donato K., et al. Executive summary: Guidelines (2013) for the management of overweight and obesity in adults. Obesity, 2014 June.
9. Tay J., Luscombe-Marsh T., Thompson CH, et al. Comparison of low- and high-carbohydrate diets for type 2 diabetes management: a randomized trial. American Journal of Clinical Nutrition, 2015; 102(4): 780.
