Calories in Protein Powder: Nutrition Facts & Serving Sizes
Per 1 scoop (45g)
Per 100g
Source: USDA FoodData Central, SR Legacy, March 2026.
One scoop of protein powder (45g) contains 175 calories and 25g of protein, making it one of the most efficient ways to hit daily protein targets. Per 100g, protein powder delivers 388 calories and 55.6g of protein, an exceptionally high protein density that no whole food matches. Phosphorus stands out at 1,272mg per 100g, which is extremely high and supports ATP synthesis critical for training performance. Potassium at 933mg per 100g supports muscle contraction and electrolyte balance. Iron at 12mg per 100g is very high, likely from plant-based protein sources such as pea or soy protein that are common in blended powders. Folate at 289mcg per 100g and zinc at 6.6mg are also notably elevated. Fat is low at 5.6g per 100g with only 1.1g saturated fat, and fiber at 6.7g per 100g adds satiety. Protein powder is a practical tool for closing the gap between dietary protein intake and training-driven protein requirements.
Nutrition Highlights
Calories by Serving Size
| Serving | Cal | Protein | Carbs | Fat | Fiber |
|---|---|---|---|---|---|
| 1 scoop (45g) | 174.6 | 25g | 13g | 2.5g | 3g |
| 100g | 388 | 55.6g | 28.9g | 5.6g | 6.7g |
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Full Nutrition Facts (per 100g)
| Nutrient | Amount | % Daily Value |
|---|---|---|
| Calories | 388 | 19% |
| Protein | 55.6g | 111% |
| Total Fat | 5.6g | 7% |
| Saturated Fat | 1.1g | 6% |
| Total Carbohydrates | 28.9g | 11% |
| Dietary Fiber | 6.7g | 24% |
| Sugars | 22.2g | 44% |
| Sodium | 733mg | 32% |
Vitamins & Minerals (per 100g)
| Nutrient | Amount | % Daily Value |
|---|---|---|
| Saturated Fat | 1.1g | 0% |
| Calcium | 178mg | 14% |
| Iron | 12mg | 67% |
| Potassium | 933mg | 20% |
| Vitamin B6 | 0.2mg | 12% |
| Magnesium | 64mg | 15% |
| Phosphorus | 1272mg | 102% |
| Zinc | 6.6mg | 60% |
| Selenium | 1.3mcg | 2% |
| Folate | 289mcg | 72% |
| Thiamin (B1) | 0.3mg | 25% |
| Riboflavin (B2) | 0.2mg | 15% |
| Niacin (B3) | 2.4mg | 15% |
% Daily Values based on a 2,000 calorie diet (FDA reference).
Health Benefits of Protein Powder
Protein powder delivers more protein per calorie than virtually any whole food, with 55.6g of protein per 100g compared to 20-27g for most meats. For anyone struggling to hit a daily protein target of 160-200g from whole foods alone, a single or double scoop fills the gap without adding significant calories from fat or carbs.
Phosphorus at 1,272mg per 100g is exceptionally high and plays a direct role in ATP resynthesis during and after training. Higher phosphorus availability supports faster recovery between sets and sessions. Potassium at 933mg per 100g helps restore intracellular electrolyte balance depleted through sweat during hard training.
Zinc at 6.6mg per 100g supports testosterone production, immune function, and protein metabolism. All three are directly relevant to muscle building outcomes. Iron at 12mg per 100g supports oxygen transport to working muscles, though the bioavailability of non-heme iron from plant sources is lower than heme iron from meat.
Folate at 289mcg per 100g supports DNA synthesis and cell replication, both of which accelerate during periods of muscle hypertrophy. The 6.7g of fiber per 100g (often from added chicory root or psyllium in blended powders) improves gut health and slows digestion of the shake, extending the amino acid release window.
The very low saturated fat (1.1g per 100g) and zero cholesterol make protein powder one of the cleanest protein sources for cardiovascular health compared to fatty animal proteins.
Dietary Considerations
Protein powder compatibility depends heavily on the source. Whey and casein proteins are not suitable for vegans or those with dairy allergies. Plant-based protein powders (pea, soy, rice, hemp) are vegan and dairy-free. Most protein powders are gluten-free, but cross-contamination can occur in facilities processing oat-based products, so certified gluten-free options are available for those with celiac disease. Carbs at 28.9g per 100g (13g per scoop) make most standard protein powders unsuitable for strict keto, though unflavored or low-carb whey isolate options exist with under 2g carbs per scoop. Sodium at 733mg per 100g (330mg per scoop) is moderate. For weight loss, the high protein-to-calorie ratio makes protein powder an efficient supplement for hitting daily targets without excess calories.
Daily Intake (100g)
100g of protein powder provides 19% of a 2,000-calorie diet.
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Frequently Asked Questions
How many calories in protein powder?
Protein powder contains 388 calories per 100g. A standard scoop (45g) contains approximately 175 calories with 25g protein, 13g carbs, and 2.5g fat.
Is protein powder good for weight loss?
Yes, protein powder is effective for weight loss because high protein intake preserves muscle mass during a calorie deficit and promotes satiety. A scoop mixed in water adds 175 calories and 25g protein with minimal fat, making it easy to hit protein targets without excess calories.
How much protein is in protein powder?
Protein powder contains 55.6g of protein per 100g. A standard scoop (45g) provides 25g of protein, which is roughly equivalent to a 4oz chicken breast in protein content.
When should you take protein powder?
Protein powder is most commonly used post-workout to supply amino acids for muscle repair, or between meals to maintain protein intake throughout the day. The timing is less critical than total daily protein intake, so use it whenever it is most convenient to hit your protein target.
What is the difference between whey and plant protein powder?
Whey protein is a complete protein derived from milk, digests quickly, and has a high leucine content that drives muscle protein synthesis. Plant protein powders (pea, soy, rice) are suitable for vegans but may need to be blended to provide all essential amino acids. Whey generally has a slight edge for post-workout use, but both are effective for meeting daily protein targets.
Is protein powder keto?
Standard protein powder is not keto-compatible at 13g of carbs per scoop. However, unflavored whey protein isolate or specifically formulated low-carb protein powders can have under 2g of carbs per serving, making them suitable for keto.
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