Carb cycling is not a new strategy but has been used mostly by elite endurance athletes to maximise performance. How it works is during days of competition or training athletes would include carbohydrate in their diet but on off days carbohydrate intake would drop substantially. The theory behind this is by increasing carbohydrates when you exercise intensely you will use the fat as a fuel source as you have ‘trained’ this in your body on your days off.
How can you use carb cycling? The theory is the same in that on your more intense workout days e.g. weights or cardio you include more carbohydrates. On your days off or when you are participating in lighter exercise like yoga or walking your carbohydrate intake is significantly reduced. It is hypothesised that your body starts to use its fat stores more as fuel and can help you shift those extra unwanted kilos.
Any potential problems?
- You may lose weight over a day quickly, but this tends to be water weight as for every gram of the stored carbohydrate in your body known as glycogen it is attached to 2g of water.
- If you are exercising intensely most days this can lead to effects seen on the keto diet like GI discomfort, horrible breath, inability to concentrate, headache and fatigue.
- If you have low blood sugars this diet is a no go as regular and sustaining carbs are needed to prevent you from passing out.
- Those with Diabetes following carbohydrate exchanges need carbs for health and wellbeing and should not follow this plan.
- If the diet is not founded on healthy forms of carbohydrates, fats, protein, fruit and vegetables it can lead to nutrient deficiencies in B6, folate, thiamine, vitamin E and A, potassium, iron, calcium as well as fibre.
The upside of this way of eating.
- You can still include carbohydrates in your diet, unlike other diets like the ketogenic diet which cut out most carbs all the time.
- Having a greater focus on how you are eating and what you are eating may lead to improved nutrition e.g. you become more aware of the 3pm doughnut which creeps in every day.
- It may be a sustainable way of eating if healthy fats, lean meats and whole grains are included rather than refined sugars and large amounts of saturated animal and trans fats.
Take home message:
There is currently not a scientific backing to support this strategy for weight loss. Also, if you have a strong bond with the carbohydrates in your life I do not recommend carb cycling. Instead focus on how many calories are coming in and shifting your focus on your portion sizes and quality of carbohydrates over restricting them. At the end of the day a calorie is still a calorie no matter it’s forms and if you are exceeding your energy needs you will not lose weight no matter if your diet is mostly fat and protein or a mixture of carbohydrates, fat and protein.
References
- Pool C, Wilborn C, Taylor L, Kerksick C. The role of post-exercise nutrient administration on muscle protein synthesis and glycogen synthesis. J Sports Sci Med. 2010;9(3):354-363.
- D'Anci KE, Watts KL, Kanarek RB, Taylor HA. Low-carbohydrate weight-loss diets. Effects on cognition and mood. Appetite. 2009;52(1):96-103.
- Wylie-Rosett J, Aebersold K, Conlon B, Isasi CR, Ostrovsky NW. Health effects of low-carbohydrate diets: where should new research go? Curr Diab Rep. 2013;13(2):271-278.
- Freedman MR, King J, Kennedy E. Popular diets: a scientific review. Obes Res. 2001;9(Suppl 1):1S-40S.
- Bloom WL. Carbohydrates and water balance. Am J Clin Nutr. 1967;20(2):157-162.
