Most adults need 0.8 grams of protein per kilogram of body weight per day and should get 45 to 65 percent of their total calories from carbohydrates. For a 150-pound person, that translates to roughly 55 grams of protein and 225 to 355 grams of carbs on a 2,000-calorie diet. But those are baseline numbers for someone who isn’t particularly active, and your actual needs shift significantly based on your goals, your age, and how much you move.
Protein: Your Baseline and Beyond
The standard recommendation of 0.8 grams per kilogram (about 0.36 grams per pound) is enough to prevent deficiency in a sedentary adult. For a 165-pound person, that comes out to roughly 60 grams per day. But “enough to prevent deficiency” and “enough to thrive” are two different things, and most people benefit from eating more than the bare minimum.
If you’re trying to lose weight, aim for 1.0 to 1.2 grams per kilogram. For that same 150-pound person, that’s about 68 to 82 grams daily. The extra protein helps preserve muscle while you’re in a calorie deficit, which matters because losing muscle slows your metabolism and makes weight regain more likely. If you’re strength training or doing regular endurance exercise, the range climbs to 1.4 to 2.0 grams per kilogram. That’s 95 to 136 grams for a 150-pound person, a meaningful jump from the baseline.
There is a ceiling. Consuming more than about 0.9 grams per pound of body weight (roughly 150 grams a day for a 165-pound person) can strain the kidneys over time and offers diminishing returns for most people. Very high intakes above 3.0 grams per kilogram have shown some body composition benefits in resistance-trained athletes, but that’s a narrow population doing serious training, not a general recommendation.
How to Spread Protein Across the Day
Your body can only use so much protein at once to build and repair muscle. Research shows that about 0.25 grams per kilogram per meal, or roughly 20 to 40 grams in absolute terms, is the sweet spot for younger adults. Older adults need a higher dose per meal, closer to 0.4 grams per kilogram, because aging muscle tissue responds less efficiently to protein.
This means eating 80 grams of protein in one sitting and skipping it the rest of the day is less effective than splitting your intake across three or four meals. A practical approach: aim for a palm-sized portion of a protein-rich food at each meal and you’ll likely land in the right range without counting grams.
Carbohydrates: Why the Range Is So Wide
The recommended range of 45 to 65 percent of calories from carbohydrates is deliberately broad because carb needs vary more than protein needs. Someone sitting at a desk all day doesn’t need the same fuel as someone running for an hour every morning. On a 2,000-calorie diet, 45 percent works out to 225 grams and 65 percent works out to 325 grams. That’s a 100-gram difference, which is roughly equivalent to four slices of bread and a banana.
Your brain alone uses about 100 grams of glucose per day just to function. That’s a non-negotiable energy cost your body covers whether you eat carbs directly or forces your liver to manufacture glucose from other sources. Very low-carb diets can work for some goals, but they’re fighting against your brain’s baseline fuel demand, which is why many people feel foggy or irritable during the first week of cutting carbs sharply.
Carbs Based on How Much You Move
If you exercise, activity-specific carbohydrate targets in grams per kilogram of body weight are more useful than percentages:
- Light activity (under 1 hour a day): 3 to 5 grams per kilogram. For a 150-pound person, that’s 204 to 340 grams.
- Moderate activity (about 1 hour a day): 5 to 7 grams per kilogram, or 340 to 476 grams.
- High-intensity training (1 to 3 hours a day): 6 to 10 grams per kilogram, or 408 to 680 grams.
Endurance athletes in particular need to prioritize carbohydrates. Pairing adequate carbs with protein after long sessions helps offset muscle damage and speeds recovery. Strength athletes can get away with lower carb intakes, but cutting them too aggressively often hurts workout performance before it helps body composition.
Carb Quality Matters as Much as Quantity
Not all carbohydrate grams are equal. Fiber, a type of carbohydrate your body can’t digest for energy, plays a critical role in gut health, blood sugar stability, and satiety. Women need about 25 grams of fiber per day and men need about 38 grams, but most Americans fall well short. Whole grains, beans, vegetables, and fruit deliver carbohydrates packaged with fiber, vitamins, and minerals. Refined sugars and white flour deliver the same calorie count with almost none of those benefits.
A simple rule: if most of your carbs come from foods that still look like they grew out of the ground, you’re probably in good shape on quality. If most come from packages with long ingredient lists, the grams on the label are doing less for you than they could.
Putting Protein and Carbs Together
Macronutrient targets only help if they fit your actual life. Here’s a practical framework for a 150-pound (68-kilogram) person at three different activity levels:
- Mostly sedentary: ~55 g protein, ~225 to 300 g carbs per day
- Moderate exercise (3 to 5 sessions per week): ~80 to 100 g protein, ~300 to 400 g carbs
- Intense training (daily, 1+ hours): ~100 to 136 g protein, ~400 to 550 g carbs
These ranges assume a calorie intake that matches your goals. If you’re eating in a deficit to lose weight, both numbers tilt toward the lower end but protein stays proportionally higher to protect muscle. If you’re eating at maintenance or in a surplus to build muscle, carbs can push toward the upper end because you need the fuel to train hard enough to stimulate growth.
Adjustments for Adults Over 65
Aging changes the equation, especially for protein. Older adults lose muscle mass more readily (a process called sarcopenia), and their muscles are less responsive to protein intake meal by meal. Eating above the baseline recommendation becomes more important, not less. Combining higher protein intake with resistance exercise produces the biggest improvements in muscle mass and strength in this age group. Aiming for 1.0 to 1.2 grams of protein per kilogram is a reasonable starting point for older adults who want to stay strong and mobile. Carbohydrate needs don’t change dramatically with age, though prioritizing fiber-rich sources becomes even more important for digestive health and blood sugar control.