January 28, 2011
This article is Part 1 of a two-part series from Ben Greenfield on the benefits of carbohydrate restriction during training. If you have questions or comments, please leave them below!
You roll out of bed and glance at your watch. You've got a 12 mile run on-tap for the day, and limited time to get it in. Do you lace up and head out without grabbing a banana, bagel or handful of sports gels, or do you make sure you have sugar to consume before and during the effort?
If you're a good little endurance athlete, you probably raised your hand and said “Eat!”.
But the entire basis for posing a question like this is based on the fact that multiple research studies have proven that several components of your aerobic fitness are enhanced when you train with low levels of storage carbohydrate or low levels of carbohydrate intake during the exercise session.
Sorry, Wheaties, but it's true: you don't actually have to be a carbaholic to be an endurance athlete.
Now don't get me wrong: there is absolutely no argument that high-carbohydrate intake before an endurance exercise session can postpone fatigue and improve performance. So it's no surprise that the “gold-standard” recommendation from most sports nutritionists is to consume a diet that provides high carbohydrate availability before and during exercise.
But how superior is a high-carbohydrate intake to the polar opposite: eating nothing at all?
A study in the 2010 Medicine and Science in Sports and Exercise Journal suggested the answer to this question when it coined the term “train low, compete high” in response to results that showed untrained individuals achieving better training adaptations and aerobic capacity after 10 weeks of training with low carbohydrate availability, compared to subjects who had high carbohydrate intake before and during exercise.
Another study in the Journal of Applied Physiology showed that trained individuals who performed twice a day training sessions without eating for 2 hours after the first session (thus depleting carbohydrate stores with the first session) experienced a better ability to store carbohydrate, use carbohydrate as energy, and burn fat – with no loss in performance compared to a group that only trained once per day and ate carbohydrates afterwards.
Yet another follow-up study in trained cyclists performed high intensity interval training with no carbohydrate intake showed improved fat utilization and an increase in the enzymes involved in energy metabolism, again, with no loss of performance.
Finally, current research shows that when carbohydrate stores are depleted by almost 50%, there is evidence that there is actually increased stimulus for enhanced enzyme activity in skeletal muscle, which is a good thing, since it means you can more efficiently produce energy from fuel.
And what about eating carbohydrate during training?
Despite the handy sports gel chamber enhanced water bottles on those fancy new bikes, and the tray for your sports gels on the gym's treadmill, as long as the training session is not performed in a carbohydrate depleted state, and does not exceed about 2 and a half hours, there is no evidence to show that avoiding carbohydrate during the session will reduce performance, and there is research that actually shows quite the contrary – no loss of performance!
Whether any of these benefits are due to decreased carbohydrate use or increased fat use is unclear, but there are obviously benefits to going low carbohydrate before and during training.
In summary, if you restrict carbohydrates before, during or after training you may:
#1: Increase activity of the biological mechanisms responsible for building and repairing lean muscle tissue.
#2: Increase ability to preserve and ration valuable carbohydrate stores.
#3: Increase fat utilization during exercise.
#4: Increase the activity of the enzymes responsible for metabolizing carbohydrates during high intensity exercise, such as racing.
In Part II of this series, which will be available at http://www.rockstartriathlete.com on Friday, February 4, you'll learn exactly what happens inside your body when you restrict carbohydrate intake, and get 5 instantly practical ways to cut carbohydrates in your training and racing, along with the advantages and disadvantages of each approach.
If you have questions or comments, please leave them below!
For loosing weight we have to avoid carbs. If we consume carbs there is no effect of that.
Hi Ben,
I am a strength Athlete and I wished to understand if I can have Carbs post workout after which is around one in afternoon. I restrict carbs until I train, so morning light stretches, coffee, cold shower, then hard workout at 10:00 am. Lunch by 1. So can I have carbs, here ? With my protein meal. Then I will have carbs in evening again right with protein meal ? Will that be a carb meal ? Will it be same if I only run next day and don’t lift then ?
Thank you 🙏
Hey Ben I’ve been following a keto plan, but now im starting track I have only been eating vegetables for my carbs, and fats have come from cocconut oil, butter, olive oil, and fatty meats, but now im trying to achieve a 5 min mile but want to keep insulin low and carbs low for all the benefits is there a way I can use carbs to achieve my goal with minimal amount of carbs as possible, when do you recommend me eat carbs ,and what type of carbs should I eat.
Check this: https://bengreenfieldfitness.com/2015/12/how-to-g… and this: https://bengreenfieldfitness.com/2015/02/ketogeni… and let me know if you have any other questions.
I don't eat high card breakfast unless I'm going to be out 2 + hours straight, AND, if I'm going to be > 80% of MHR. So with out reading the articles, I believe it. Hey Ben, can you talk about this on your next podcast?
Interesting article. I am still eating my oatmeal in the morning, about an hour before I train. Eating too much kills my energy, not eating anything does the same; a small bowl of oats prepared with milk and honey always does the trick.
i just saw an ad. on t.v. for uncle ben's rice. it's suppose to have all the nutreients of brown rice but have the taste of white rice. do you know anything about that?
scott
So Ben, what about the recovery drink taken within 20 min after my typical 1hr workout? Should I leave the carb sources OUT of that protein drink? The wisdom I got from you has been 3:1 carb:protein blend in order to help muscle recovery and prevent catabolizing muscle?
Read this: http://www.rockstartriathlete.com/putting-the-pre…
Way to go with the footnotes!! Keep us up to date and in line with our workouts. Science is what it is all about and Ben, you are on the cutting edge. Thanks for all you do.
bill.
What about eating afterwards. I am reading Art De Vany's new book The New Evolution Diet. He says not to eat an hour after exercise to give fat burning and growth hormones time to act before eating and thus secreting more insulin.
I'm trying to get Art on the podcast, so stay tuned!
if you followed this plan what would you eat? what if you go longer than 2.5 hrs.?
scott
It's pretty simple. Just include a session or two a week where you exercise in a fasted or semifasted state, or just do a long workout where you fuel with fewer calories than you normally would. You can still eat carbs. It's not a "plan", just a strategy.
Ben great article. I have just started the Zone eating proscription and hearing about lower carb intake being beneficial for exercise alleviates some fears. Thank you for your services.
you know ben, without knowing any of this, that is how i dropped from 235lbs to 165lbs when i first started exercising. i always worked out early in the morning and never ate anything before heading out.
I'm so confused . . .
about what?
But you said in your book Holistic fueling that we should eat carbohydrates before workouts….
I'd be a pretty poor nutritionist if I didn't pay attention to research. And it is becoming clear that you don't need to to eat carbs before *every* workout.
Hey Ben, any way you can post the details of your sources?
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and the primary source: From Exercise and Sport Sciences Reviews
Carbohydrate Availability and Training Adaptation: Effects on Cell Metabolism
Makes sense. So, I have an 18 miler tomorrow with 10 at marathon pace. Should I consume anything before and/or during the run?
Not advised. But what you could do is go the first HOUR without fuel OR if you plan on consuming 300 calories/hr in the marathon, consume 150-200/hr during this training run.