Protein requirements and the Keto Diet
One of the most common questions or misunderstandings I hear from people about low-carb or ketogenic diets is “How much protein do you need on a ketogenic diet?”
Some people mistakenly think of the keto diet as being “high protein.”
The ketogenic diet is a low-carb diet. If you remember nothing else, just remember that keto is low-carb and you should do fine on the diet.
Protein Requirements on Keto Diet
Your protein requirement while on keto also depend on a couple of other factors.
- Activity level – if you’re exercising or not.
- If you are just starting keto and have a lot of weight to lose.
- If you have been doing keto for a while and have already lost a lot of weight or just looking to maintain the weight you are at currently.
What are the minimum protein requirements on a ketogenic low-carb diet?
Let’s start with the minimum protein requirements for adults in general.
The RDA guidelines for protein intake for adults is roughly 0.8 grams of protein per kilogram of body weight (0.8 grams/kg) or about 0.35 grams per pound (0.35 grams/lb).
For a 150 lb (68 kg) woman, that is:
0.35 grams/lbs x 150 lbs or 0.8 grams/kg x 68 kg = 52.5 grams of protein per day
For a 220-pound adult male (or 100 kg) that is either:
0.35 grams/lb x 220 lbs or 0.8 grams/kg x 100kg = 77 grams of protein per day
Remember that the RDA guidelines are set for the typical inactive adult American, and there’s debate if these protein guidelines should be adjusted higher since some adults have a hard time meeting even these minimal daily protein recommendations.
Protein and activity levels
If you’re active, you’ll need more protein to help rebuild and grow new muscle.
Protein Requirements for Endurance Athletes (Runners/triathletes, etc)
A lot of traditional high-carb diet endurance athletes fail to get enough protein, especially in the longer-distance endurance athletes like marathon runners or Ironman distance triathletes.
Long-distance running, cycling, swimming, and hiking all cause muscle damage that needs to be repaired. That process of repairing muscle requires protein!
Endurance athletes should eat about 1.2 to 1.4 grams of protein per kg of body weight, or 0.55 to 0.65 grams per pound of body weight per day.
So our 150-pound (68 kg) female would need between 82.5 to 97.5 grams of protein per day:
0.55 grams/lbs x 150 lbs or 1.2 grams/kg x 68 kg = 82.5 grams of protein per day
0.65 grams/lbs x 150 lbs or 1.4 grams/kg x 68 kg = 97.5 grams of protein per day
While our 220-pound (100 kg) male would need to increase his protein intake to
0.55grams/lbs x 220 lbs or 1.2 grams/kg x 100 kg = 120 grams of protein per day
0.65 grams/lbs x 220 lbs or 1.4 grams/kg x 100 kg = 143 grams of protein per day
A lot of the endurance athletes that I have cared for over the years fall short of these increased daily protein guidelines and I’d say that some of the performance issues they sometimes struggle with are because their bodies can’t recover and repair muscle quick enough after a hard workout.
Some endurance athletes are worried that the added protein will make them “bulky” and put on too much muscle. But that’s really not a true concern with endurance athletes since they aren’t doing enough low rep, heavier weight training to gain substantial muscle bulk.
Protein Requirements for gaining muscle (strength athletes/bodybuilders) on ketogenic diets
Most strength and power athletes, as well as bodybuilders, understand the need for added protein with their increased activity levels.
To build muscle and size, the recommended daily protein intake is about 1.6 to 2.0 grams of protein per kilogram of body weight (or about 0.75 to 1.0 grams per pound).
But I still find every once in a while find a strength athlete whose protein intake is too low.
For our 150-lb (68kg) female, her daily protein requirement increases to:
0.75grams/lbs x 150 lbs or 1.6grams/kg x 68 kg = 112.5 grams of protein per day
1.0 grams/lbs x 150 lbs or 2.0 grams/kg x 68 kg = 150 grams of protein per day
And our 220 lb (100 kg) male will see his protein requirements increase to:
0.75grams/lbs x 220 lbs or 1.6grams/kg x 100 kg = 160 grams of protein per day
1.0 grams/lbs x 220 lbs or 2.0 grams/kg x 100 kg = 200 grams of protein per day.
Protein Requirements for weight loss on the ketogenic diet
The final group is the people trying to lose weight. One of the biggest problems with a lot of the low-calorie diets while people can lose weight on them, they end up losing muscle mass along with some fat. While their weight loss makes them lighter, they had to sacrifice some muscle to get there. Usually, when someone says they want to lose weight, they mean they want to lose just fat! People that are trying to lose weight, still have a higher protein requirement. In fact, dieters that have a higher protein intake where they get around 30% of their calories from protein lose more weight (and fat) than dieters that cut their protein intake to 15% of their total calories. It’s important to still need to try to meet at least the RDA guidelines for protein which would be Some severe calorie-restricted weight loss programs use a protein-sparing modified fast to prevent excessive muscle or lean tissue loss. Still, the majority of calorie-restriction diets also cause muscle wasting.
How are protein requirements different on the ketogenic diet?
One of the advantages I’ve seen in patients that have gone on the ketogenic diet is that while they still lose weight while going keto, the majority of their weight loss is fat and not muscle. Even though that can still eat fewer calories on keto, being in ketosis seems to tell the body to burn fat and not tear down muscle.
If we look at a lower-calorie ketogenic diet for weight loss, the ketogenic diet does appear to spare muscle when weight is lost. There is a small amount of muscle loss at the very start of the ketogenic diet, but if you’re on a well-formulated ketogenic diet, the amount of muscle or lean body mass lost is minimal in the range of 1 to 2 pounds of lean tissue in the first week (Davis 1990 and Phinney 1983).
Some people read about how too much protein on the ketogenic diet can kick you out of ketosis. While that’s true for some people, the solution is slowly dropping your protein intake until you see a rise in your blood ketone levels.
I noticed this muscle-sparing effect myself when I restarted my keto diet journey a couple of years ago and was able to build muscle on the ketogenic diet while still losing a substantial amount of fat.
When I switched to a low-fat/ high-carb diet later, I actually started to lose muscle with the fat!
Read about my experience training for a men’s physique show while on a keto diet. And if you’re looking for a good review article on ketogenic diet and muscle hypertrophy, read through this review article.