Bodybuilding legend Arnold Schwarzenegger‘s all about protein, but carbohydrate intake might be the missing puzzle piece to more growth. In a recent Arnold’s Pump Club newsletter, published on August 27, 2025, he discussed the muscle-building advantages of extra carb intake.
“If you’ve been laser-focused on hitting your protein goals while cutting carbs to build muscle, this might flip everything you thought you knew about gaining size.”
Having conquered the Mr. Olympia throne for seven years, Schwarzenegger is a living legend, still helping grow bodybuilding. In retirement, his involvement in the sport hasn’t waned; he hosts the annual Arnold Sports Festival every year in March, celebrating fitness and health.
Schwarzenegger’s nutrition approach has changed since hanging up his posing trunks. He limits his red meat intake, and prioritizes heart health — especially since having a pacemaker installed to help regulate his heart’s rhythm.
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Arnold Schwarzenegger Discusses How to Use Carbs to ‘Maximize Muscle Gain’: ‘It’s Not Just About Protein’
In the newsletter, Schwarzenegger touted the muscle-building advantages of taking in extra carbohydrates.
“Why Carbs Are Your Muscle-Building Advantage
Researchers found that eating more carbohydrates—not just more protein—might be the missing piece in your muscle-building puzzle.”
In the study, scientists divided participants into two groups. One group consumed 10% more calories from protein, while the other ate 40% more calories, mostly from carbohydrates. Ultimately, the group that ate the massive surplus with carbs gained muscle mass, whereas the group that ate 10% more calories from protein didn’t.
“Scientists split participants into two groups for six weeks. One group ate just 10 percent more calories than usual, with all those extra calories coming from protein. The other group went bigger: 40 percent more calories, but here’s the kicker—75 percent of those extra calories came from carbohydrates, not protein.”
“Those who ate a massive carb surplus gained actual muscle mass, while the protein-only group gained virtually nothing.”
Schwarzenegger adds that carbs aren’t just for bigger muscles; they are also essential to recovery.
“Think of protein as the building material for your muscles, but carbohydrates as the construction crew. When you eat carbs, they trigger insulin release, which doesn’t just store energy—it actively signals your body to build muscle. Carbs also replenish your muscle glycogen stores, providing the energy your body needs to utilize that protein for construction rather than just burning it for fuel.”
According to the seven-time Mr. O, if your goal is to maximize muscle gain, you need to increase calories from protein and carbs.
“This wasn’t just weight gain or water retention—the researchers used precise four-compartment body composition analysis to measure actual muscle protein mass. The group that ate substantially more calories, primarily from carbs, literally built more muscle tissue than the group that just added protein.”
“If your goal is to maximize muscle gain, you need to bump up calories more than you think, but it’s not just about protein. Most of those extra calories should come from high-quality carbs, such as rice, potatoes, oats, and fruits, which will support your workouts. Maintain a steady protein intake, ranging from approximately 0.7 to 1 gram per pound of your goal body weight (or 1.6 g/kg to 2.2 g/kg).”
It should be noted that the higher-calorie group gained some fat alongside muscle.
“Keep in mind that the higher-calorie group also gained some fat alongside muscle (the two were strongly correlated), which is normal during a maximum muscle-building phase.”
He said it’s also important to consider individual body fat to determine the best course of action for your physique.
“The key: determining your current body fat levels. If you’re more than 15 percent body fat, you might be best served by reducing body fat or focusing on body recomposition (losing fat and increasing muscle) rather than going into a pure muscle-building phase, which could increase muscle mass but also fat mass.”
Schwarzenegger has taken a closer look at bodybuilding’s most popular carb source — white rice. He broke down studies around white rice and confirmed that eating it consistently won’t cause fat gain. Instead, he emphasized that calorie control is the biggest driver of fat loss.
At 78 years old, “The Austrian Oak” wants to retain as much lean muscle as possible. He believes incorporating extra carbs can not only bolster recovery but also help with continued muscle growth.
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