Carbohydrates Eat less over time
Like protein, adequate intake of carbohydrates can positively affect muscle protein synthesis rates. However, compared to their younger counterparts, older adults may need fewer carbs to experience muscle growth.
The primary way carbohydrates influence muscle growth is by increasing insulin secretion. Insulin helps shuttle available amino acids to cells to jump-start the muscle growth and repair process. In this sense, a fair amount of carbohydrates are still needed even in your later decades of life to help maintain and grow muscle.
Carbohydrates consumed together with protein appear to have a greater anabolic effect in adults than simply consuming protein alone. It also appears that insulin can still guard against protein breakdown in adults, meaning it could have a “muscle-sparing” effect. Additionally, there is some evidence that eating carbs can prolong the body’s muscle-building response to amino acids.
In short, you can still benefit from carbs as you get older. But because physical activity and metabolic rate tend to decline as you age, you probably don’t need nearly as many of them. As your protein intake goes up with age, your carbohydrate intake can comparatively go down.
Muscle-building carbohydrate recommendations by age:
- < 20 years: 1.8-2.6 grams per pound of body weight
- 21-40 years: 1.5-2.3 grams per pound of body weight
- 41-65 years: 1.2-2 grams per pound of body weight
- > 65 years: 0.8-1.7 grams per pound of body weight
It’s worth repeating here that these recommendations are for maximizing muscle gain, so they will need to be adjusted for individuals wanting to lose body fat. Additionally, as I mentioned in my PH3 Power and Hypertrophy Trainer, individuals vary wildly in their ability to “tolerate” carbs—that is, eat them without turning them into body fat.
So consider these numbers simply to be a start to the conversation. While I think the protein numbers are more or less solid, these carb recommendations definitely aren’t set in stone.