If you’ve been strength training consistently for weeks without seeing the gains you want, look at the other half of the equation: what you’re eating.
Without the right nutrients, the weights you lift won’t pay off as much. “It’s like if you’re trying to build a house but don’t have any lumber. You need the raw materials to build muscle – that’s what nutrition provides,” says Claire Shorenstein, RD, a board-certified sports dietitian in Aptos, California.
The food you put in your body not only affects how your workout feels, but also how well your muscles rebuild and grow afterward.
How Your Diet Affects Muscle Gain
When you make a muscle work hard by lifting heavy weights or doing a high number of repetitions, you create microscopic tears in the muscle fibers. As the body repairs that tissue after multiple workouts, you end up with stronger, bigger muscles.
How you eat can influence this process in a couple of ways. First, eating protein after a workout provides the amino acids that initiate muscle protein synthesis, which is the process of rebuilding muscle tissue.
But you also need to give your muscles enough energy to contract when you work out, and that energy will primarily come from carbohydrates and fats. “Everybody is paying attention to protein right now, but making sure that the muscle has enough energy to do its job is key,” says Rachele Pojednic, PhD, CSCS, the director of education at Stanford Lifestyle Medicine in Palo Alto, California. If you don’t have enough carbs and fat in your diet, she says, your muscles will fatigue sooner, your strength will plateau, and you’ll face a higher risk of injury.
That’s because carbs, which are stored in muscles as glycogen, are the body’s preferred fuel for high-intensity activity. The reason? They convert to energy more easily. “We can burn both fat and carbohydrate for energy, but fat is a lot less efficient,” Shorenstein says.
And, since your muscles (and liver) can store only a limited amount of glycogen, you need to eat enough carbohydrates before exercise so it’s readily available.
Does It Matter What Type of Strength Training I’m Doing?
Not every strength training session looks the same. Traditional weightlifting uses weights or resistance machines to work specific muscle groups to exhaustion, usually with heavy loads, few repetitions and defined rest periods between sets. Bodyweight training, on the other hand, uses only your body weight and gravity for resistance, with no external weights; the challenge usually comes from higher rep ranges. Circuit training also involves rotating through various exercises with low-to-moderate weights while taking little to no rest to raise your heart rate and challenge your muscles.
No matter which approach you take, your training intensity will affect how many calories you need, Dr. Pojednic says. The more hours you spend strength training each week and the harder your workouts are, the more total calories you’ll need. Adequate calories ensure that your body has enough energy to perform essential functions while fueling your athletic performance.
What those calories are made of matters, too, Pojednic adds. The right balance of macronutrients helps you build and maintain muscle as you age. As a general rule, the National Academies of Sciences, Engineering, and Medicine recommend that protein make up about 10 to 35 percent of your diet, carbs 45 to 65 percent, and fats 20 to 35 percent.
When you’re specifically focused on building or maintaining muscle mass, most experts recommend aiming for about 1.4 to 2 grams (g) of protein per kilogram (kg) of body weight per day. (To convert your weight from pounds [lb] to kg, divide it by 2.2.)
Beyond body size, your workouts also determine where you should aim within that range. People who meet the physical activity guidelines of two strength workouts per week might do fine with 1.4 g of protein per kg daily. Still, athletes training twice as often for competitive powerlifting events would be better off aiming closer to 2 g. “If your training volume or intensity is very high, you need more protein relative to less active people,” Shorenstein says.
She adds that you also want more carbs if you’re doing more intense strength workouts, like high-intensity interval training (HIIT). “Increased intensity burns through carbs more quickly,” Shorenstein says.
How to Eat Better When You’re Strength Training: 6 Tips
In addition to getting ample protein, carbs, and fats, there are a few other ways your diet can support your strength training.
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Spread out your protein. Your body doesn’t hold on to amino acids the way it does carbs and fat (any extra gets converted into sugar or body fat), so you need to keep introducing them. For this reason, Shorenstein suggests getting 25 to 40 g of protein in every meal, and also having a snack with 10 to 20 g of protein before your workout. Then, ideally, you’ll have a full meal afterward. “That way you have the resources you need to rebuild the muscle,” Shorenstein says. But don’t fret if you can’t eat right after the gym: Protein timing matters less than giving your body a steady dose throughout the day.
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Don’t train on an empty stomach. Since carbs are your body’s primary fuel source, you don’t want your glycogen stores (which come from carbs) to be too low before your workout. But if you train first thing in the morning, you might not have the appetite for – or the time to digest – a full meal. Shorenstein suggests at least getting a high-carb snack with a little protein and fat before a strength session. For example, peanut butter and banana on a slice of toast. “If you train fasted, you may end up breaking down muscle for energy, which you never want,” Shorenstein says.
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Stay hydrated. Research suggests that even a 2 percent body weight loss from dehydration can impair athletic performance. “If you’re dehydrated, the likelihood that you are going to be able to execute your lift and then recover appropriately is pretty low, which means that you’re also going to be at risk for injury,” Pojednic says. To stay properly hydrated, she recommends paying attention to thirst and urine color, which should be just slightly yellow rather than bright yellow, orange, or brown.
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Don’t overdo protein snacks and powders. You can get protein seemingly anywhere these days, from soda to oatmeal. Occasionally supplementing with these products can help you meet your protein goals. Focus on whole, high-protein foods like lean meats, dairy, eggs, nuts, seeds, and legumes. “You’re going to get so much more nutrition out of lean ground beef, like iron, compared to some protein pretzel,” Shorenstein says.
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Keep eating on rest days. Your body recovers and repairs muscle tissue for approximately 48 hours after your workout, Pojednic says. To fuel that process, you’ll need to give your body plenty of nutrients. “If you don’t eat sufficiently on rest days, you can actually impair that regeneration process because the building blocks and the energy required to rebuild your muscles are simply not in circulation,” Pojednic says.
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Keep tabs on calcium and vitamin D. Bone health is one of the most compelling reasons to start strength training. Strength training supports bone density because contracting muscles pull on bones, triggering bone tissue growth. To maximize those benefits, Shorenstein recommends being deliberate about your calcium and vitamin D intake (vitamin D helps you absorb calcium). Experts recommend that adults get 1,000 to 1,200 milligrams (mg) of calcium per day from foods like milk, yogurt, cheese, and certain vegetables such as broccoli and kale. For vitamin D, adults should get 600 to 800 international units (IUs) a day from foods like fatty fish, egg yolks, cheese, and fortified milk. If you’re worried you’re not getting enough of these nutrients in your diet, talk to your doctor before taking a supplement, as too much can be harmful.
The Takeaway
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Building muscle and strength requires more than just lifting weights. Protein rebuilds muscle tissue while carbs and fat fuel your workouts, and skimping on either will limit your gains.
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Recovery happens in the 48 hours after a workout, so spread protein across meals, eat before training, and keep eating on rest days.
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Prioritize whole foods over protein supplements, and pay attention to calcium and vitamin D to support the bone health benefits of strength training.
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
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Currier BS et al. American College of Sports Medicine Position Stand. Resistance Training Prescription for Muscle Function, Hypertrophy, and Physical Performance in Healthy Adults: An Overview of Reviews. Medicine & Science in Sports & Exercise. April 2026.
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Try Circuit Training for a Fast, Flexible Workout. Cleveland Clinic. July 20, 2026.
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Lak M et al. Timing Matters? The Effects of Two Different Timing of High Protein Diets on Body Composition, Muscular Performance, and Biochemical Markers In Resistance-Trained Males. Frontiers in Nutrition. May 22, 2024.
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Carbohydrates: How Carbs Fit Into a Healthy Diet. Mayo Clinic. January 24, 2025.
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Francisco R et al. Recommendations for Optimizing Research Regarding the Effects of Dehydration on Athletic Performance. Sports Medicine. September 3, 2025.
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Kara Andrew, RDN, LDN
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