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How much protein and carbs you actually need to get stronger

By Katrina Watson ·

If you spend any time in strength-training corners of the internet, you’ve probably been told to eat more protein. Hit your number, prioritize it at every meal, don’t let a bad day slide. It’s good advice. It’s also, for a lot of people, the only macro anyone talks about — which means carbs quietly become the thing you deprioritize, or actively try to eat less of, without ever really deciding to.

I’ve recently been digging deeper into understanding more about nutrition, planning my meals, hitting my protein and macro goals. And after 6 weeks of hitting my protein goals consistently, I could see the lean muscle mass increasing on my weekly weigh-ins. But I also felt exhausted, and like my actual progress in the gym had flatlined.

So when I saw a recent report suggesting we’re all over-prioritizing protein and not eating enough carbs, I was intrigued to find out more.

What protein actually does — and how much you actually need

Protein’s job is straightforward: it gives your body the raw material to repair and build muscle tissue after training. The research on how much you need is genuinely settled science, not a debated corner of nutrition. The International Society of Sports Nutrition’s position stand on protein and exercise puts the range for building and maintaining muscle at 1.4–2.0g of protein per kg of bodyweight per day for most people who train — and that’s enough. More than that isn’t dangerous, but it’s also not doing extra work for you once you’re in range.

That number moves in one specific situation, which we’ll get to below.

What carbs actually do — and why “just focus on protein” undersells them

Carbs aren’t filler calories. Their specific job in a strength context is fueling the muscle itself: your muscles store carbohydrate as glycogen, and glycogen is the fuel your muscle fibers draw on during resistance training. A 2025 systematic review and meta-analysis of resistance exercise found that a single heavy training session can deplete muscle glycogen by roughly 24–40%, with the fast-twitch fibers you rely on most for heavy lifting depleted the hardest. Start a session already running low, and the same research on glycogen availability shows it can accelerate fatigue and impair the force your muscles are able to produce — which shows up as a flat, heavy-feeling session that has nothing to do with how hard you’re actually trying.

And that’s exactly how I felt. Like no matter how much I tried, some of my lifts weren’t progressing, and I wasn’t sure why.

I’m not alone — I’ve seen a few different fitness influencers talking about this recently too: that we’ve been quietly under-fueling carbs for a while. Not intentionally, but when the focus is on hitting our protein goals, it’s easy to see carbs as just where the other calories go, and for a lot of us, our brains are still wired to think less calories is always a good thing.

But does that mean we should eat more carbs, or more calories, all the time?

A 2022 systematic review specifically on carbohydrate intake and resistance training looked at long-term studies comparing higher vs. lower carb diets, and in 15 of 17 of them, higher carb intake didn’t produce significantly better strength gains than lower carb intake at the group level. So this isn’t “eat more carbs and you’ll definitely PB” — it’s closer to “if you’ve been running chronically low on carbs relative to how much you’re training, that’s a real, physiologically-grounded reason your sessions might feel harder than they should, and worth fixing before you assume the problem is your training.” Individual response varies more than average-of-a-study-group numbers can capture.

So how many carbs do you actually need?

There isn’t one universal number, because it scales with how much you’re training — but here’s a usable range. A 2019 review on nutrition for bodybuilders in a training (non-dieting) phase recommends at least 3–5g of carbs per kg of bodyweight per day to support the energy demands of resistance training, and the broader ACSM/ISSN joint position stand on nutrition and athletic performance puts moderate daily training (around an hour) at 5–7g/kg/day, scaling up from there with volume. If you train a handful of hours a week, the lower-to-middle part of that range is a reasonable starting point — not the 8–12g/kg territory built for multi-hour endurance athletes, which is a different demand entirely.

As a rough example: for a 70kg lifter in a training block, that’s somewhere around 210–350g of carbs a day — a wide range on purpose, since the right end of it depends on how much and how hard you’re actually training.

Does this change depending on your block?

Yes. What you need shifts depending on whether you’re in a block built to push numbers up, or one built to bring bodyweight down.

In a PB / performance block (training at maintenance or a slight surplus, chasing new numbers): this is exactly the scenario above. Protein stays in its normal 1.4–2.0g/kg range, and carbs should be at the higher end of what your training volume calls for — you’re not restricting calories, so there’s no reason to shortchange the fuel that directly supports harder, higher-quality sessions.

In a cut (training in a calorie deficit): this is where protein’s number actually moves. When calories are restricted, your body is more prone to breaking down muscle tissue for fuel alongside fat — so protein needs go up specifically to protect the muscle you’ve built. The same ISSN position stand recommends 2.3–3.1g/kg/day during a deficit, and research on natural bodybuilding contest preparation backs the same range for exactly this reason. Carbs are typically the macro that absorbs the rest of the deficit — which is why training on a cut tends to feel harder and flatter than training at maintenance. That’s an expected physiological tradeoff of eating less overall, not a sign that you’re doing the cut wrong or that your carbs are “too low.”

The practical version

If you’ve been hyper-focused on protein and treating carbs as an afterthought — or something to minimize — while you’re actually trying to push numbers up, that’s worth a second look. The fix isn’t complicated. It’s just usually the opposite of what the fitness-content algorithm has been telling you to focus on.

Nutrition is one lever. For the rest of the picture, see our full guide to strength training for women.

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