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You've Heard of Carb-loading, but What About Carb-cycling?

There are so many diet fads out there. I have never been a proponent of one or committed to a weight loss/strength gain nutrition program. After years of battling with body dysmorphia in my early teens and an unhealthy relationship with calorie counting (which I didn't even understand why I was doing), I now have a healthy relationship with food as fuel. I tend to eat what I want, when I want with the overall goal of fueling my body with the nutrients it needs to participate in the endurance training I love to do. But this doesn't mean that I am not intrigued by what's out there. Quite frankly I find diet fads interesting to research and understand. I heard about reverse carb cycling through social media and did a quick internet search, which opened up my eyes to the world of carb cycling. Let's see where it takes us.

There are so many diet fads out there.  I have never been a proponent of one or committed to a weight loss/strength gain nutrition program.  After years of battling with body dysmorphia in my early teens and an unhealthy relationship with calorie counting (which I didn't even understand why I was doing), I now have a healthy relationship with food as fuel.  I tend to eat what I want, when I want with the overall goal of fueling my body with the nutrients it needs to participate in the endurance training I love to do.   But this doesn't mean that I am not intrigued by what's out there.   Quite frankly I find diet fads interesting to research and understand.  I heard about reverse carb cycling through social media and did a quick internet search, which opened up my eyes to the world of carb cycling.  Let's see where it takes us.  

Chances are you have all heard of carb loading for a big race - where my runners and triathletes at?  Or maybe you heard of carb-loading for an athletic event in your earlier teen years (high school sports)?  If not, let me give you the 4-1-1.

Carb loading is the practice of eating a high carbohydrate diet for days leading up to a sports event.  Typically, carb loading is reserved for events that are longer (>/= 90 minutes) in duration.  If you are a runner, swimmer, or cycler I am sure you have participated in a carb load at some point.  Per the Mayo Clinic, the carb load is actually used to increase your muscle's glycogen (energy) stores.  Your muscles will fatigue when those glycogen stores are depleted.  With an appropriate carb load, your stamina should increase.  YAAAS.

More glycogen = improved performance and endurance + less fatigue

Typically, athletes increase their carbohydrate intake from 5-7 grams per kg of bodyweight to 8-12 grams per kg of bodyweight or nearly double.  This is done for 1-3 days prior to the event and in turn fat intake is reduced.  In addition, these athletes tend to taper their activity level for 3-4 days to allow muscles to rest and glycogen stores to build up.   Let's not forget that fueling during and after the event is just as important to maintain energy stores and replenish them, respectively.  

Okay, this should all make sense.  Unfortunately, carb loading isn't an every day lifestyle.  Although my pro-carb self wishes it was.  But there are lots of diets that consider carbohydrate manipulation to help with weight loss results.  

Carb cycling is what it sounds like-- eating a higher quantity of carbs on set days and less on others.  Essentially, planning your week into high carb, moderate carb, and/or low carb days.  

The philosophy is that high carb days are used to refuel around higher workout intensity in order to replenish glycogen stores.  Sound familiar?  The goal of low carb days is for the body to primarily use fat as an energy source and not use muscle tissue or the glycogen.  In turn, the hope is weight loss.  Now, if you eat high carb and don't pair it with high intensity exercise, you could gain weight.  One interesting trend I noticed is that in these articles high carb was actually similar to what the Mayo Clinic referenced as normal carbohydrate amount.  So high carb days in carb cycling is not the same amount of carbs as you may consume when carb loading.  

High carb = 2-2.5 g/lb of bodyweight = 4.4-5 g/kg of bodyweight
Low carb = 0.5 g/lb of bodyweight = 1.1 g/kg of bodyweight

Cutting back on carbs can cause the carb flu.  I kid you not, it's a thing.  Basically, a more intense version of "hanger".  Symptoms include mood changes, difficulty with sleep, daytime tiredness, constipation and bloating.  

Typically, I love to share the evidence-based research there is to support a topic but I was not able to find a good source.   If you know of a trial that investigates the proposed benefits oof carb cycling please let me know!

Reverse carb cycling is adjusting your diet so that you consume carbs in the later half of the day.  The proposed reason for this is to prevent insulin from spiking, but also to take advantage of hormone changes that occur in response to carbohydrate consumption.  

Eat Carbs -->  Sugar Releases Into Bloodstream --> Pancreas Releases Insulin  --> Cells Absorb Sugar --> Pancreas Releases Glucagon --> Liver Releases Stored Sugar

Eating carbs at night has been associated with increasing serotonin levels, which in turn increases melatonin and leads to improved sleep.  A good nights sleep has also been associated with consuming less calories overall.  

There is not a lot of evidence to support carb cycling works for weight loss.  What works for weight loss is a caloric deficit.  So if cycling your carbs around your exercise intensity causes a net caloric deficit then bada bing bada boom...you may start to see weight loss.

If you want to read more on the topic, this Healthline article dives into detail and even includes example schedules of the diet.  

Conquer Your Summit,
Ives Hot, PharmD, BCACP, Certified Group Fitness Trainer, PCES