I found this article by Lyle McDonald on Bodyrecomposition.com very interesting: How Many Carbohydrates Do You Need? It’s a question that I have been asking myself a lot, since I have been following the Paleo diet and actively do CrossFit every week. I wish there was an easy answer, but there isn’t. The answer is “It Depends“. It depends on who you are, your activity level, and what you want to accomplish (e.g., weight loss, endurance running, muscle building, etc.).
Interestingly, McDonald clearly states that “the minimum amount of carbohydrates that are required in a diet is zero grams per day”. Basically, your body needs glucose for “fuel” and can make it from other sources besides carbs (e.g., protein being used in the liver to make glucose). But, if you want to strength train and grow muscle, you need to ingest more total protein to make sure there is a sufficient amount to support things like protein synthesis into muscle. So, you could eat a ton of protein to prevent your body from taking all of it to create glucose or you could make sure you have enough carbs in your diet to prevent that protein loss.
The article is very detailed and I recommend that you read it, but I will try to simplify the key takeaway. If you are trying to lose weight and/or you really just do low-intensity exercise (e.g., walking 3-5 times per week), you really don’t need to increase your carbohydrates over the minimum intake level. But, if you are a high-intensity athlete (e.g., serious weight lifting and high-intensity exercise, CrossFit, endurance runners and cyclists, etc.), you will want to ensure that you are getting enough carbs in your diet to prevent protein loss. He put together a very useful table, which I have shared below, that highlights different carb requirements based on your activity.
|Circumstance||Carbohydrate Requirement||Grams for an athlete with 160 lbs. LBM|
|Physiological Requirement||0 g/day||0 g/day|
|PracticalMinimum to Avoid Muscle Breakdown2||50 g/day||50 g/day|
|Practical Minimum for Individuals Who Function Poorly In Ketosis3||100-120 g/day||100-120 g/day|
|Additional Amount to Sustain Low Intensity Exercise||Minimal approaching zero||Minimal approaching zero|
|Additional Amount Needed to Sustain Weight Training||5 g carbs. per 2 work sets4||5 g carbs. per 2 work sets4|
|Average Recommendations in Bodybuilding Nutrition||1-3 g/lb.||160-480 g/day|
|Average Recommendations by Mainstream Nutritionists||2-3 g/lb||320-480 g/day|
|Average Intake for Endurance Athletes||2 g/lb||320 g/day|
|Recommended Intake for Endurance Athletes||3-4.5 g/lb||480-720 g/day|
|Practical Maximum for Non-Carb Loading Individuals||4 g/lb||640 g/day|
|Maximal Intakes for Carb-Loading||~7 g/lb||
To put these amounts into perspective, here are a few typical foods and their carbs in grams.
Carbohydrates in Some Typical Foods
|Food||Carbs in Grams|
|Apple, medium (3 in diameter)||21 grams|
|Banana, medium (~7 in long)||24 grams|
|Broccoli (4 oz)||5 grams|
|Carrot (1/2 cup)||4 grams|
|Orange juice (8 oz)||28 grams|
|Sweet potato, medium (5″ long, 2″ in diameter)||20 grams|
So, as you can see, it’s not too hard to get the carbs you need from a few healthy foods added to your diet. For more tables on typical food carbohydrate levels, refer to these resources:
Huge food list from USDA sorted by Carbs
Huge food list from USDA sorted by Food
Nutrition for the Athlete
Another big food nutritional chart