Calories in Granola Bars: Nutrition Facts & Serving Sizes
Per 1 oz (28g)
Per 100g
Source: USDA FoodData Central, SR Legacy, March 2026.
Granola bars are compressed bars made from rolled oats, nuts, seeds, sweeteners, and binding agents like honey or syrup. A 1 oz serving (28g) delivers about 152 calories, 2.7g of protein, 15.4g of carbs, and 8.9g of fat. Per 100g they contain 536 calories, making them calorie-dense snacks comparable to nuts and nut butters. Sugar is notable at 23.6g per 100g. Magnesium at 67mg and potassium at 339mg per 100g provide solid mineral support. Vitamin E at 4.6mg per 100g is a standout, supporting antioxidant defense. Selenium at 15.7mcg adds further antioxidant coverage. Despite their reputation as a healthy snack, standard granola bars are high in added sugars and fat. Protein bars and purpose-built nutrition bars significantly outperform granola bars on protein content for calorie trade-off.
Nutrition Highlights
Calories by Serving Size
| Serving | Cal | Protein | Carbs | Fat | Fiber |
|---|---|---|---|---|---|
| 1 oz (28g) | 152.2 | 2.7g | 15.4g | 8.9g | 1.1g |
| 100g | 536 | 9.6g | 54.1g | 31.2g | 3.8g |
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Full Nutrition Facts (per 100g)
| Nutrient | Amount | % Daily Value |
|---|---|---|
| Calories | 536 | 27% |
| Protein | 9.6g | 19% |
| Total Fat | 31.2g | 40% |
| Saturated Fat | 17.1g | 86% |
| Total Carbohydrates | 54.1g | 20% |
| Dietary Fiber | 3.8g | 14% |
| Sugars | 23.6g | 47% |
| Sodium | 193mg | 8% |
| Cholesterol | 12mg | 4% |
Vitamins & Minerals (per 100g)
| Nutrient | Amount | % Daily Value |
|---|---|---|
| Saturated Fat | 17.1g | 6% |
| Cholesterol | 12mg | 4% |
| Calcium | 108mg | 8% |
| Iron | 1.5mg | 8% |
| Potassium | 339mg | 7% |
| Vitamin A | 8mcg | 1% |
| Vitamin C | 0.6mg | 1% |
| Vitamin B6 | 0.1mg | 6% |
| Vitamin B12 | 0.5mcg | 21% |
| Magnesium | 67mg | 16% |
| Phosphorus | 227mg | 18% |
| Zinc | 1.5mg | 14% |
| Selenium | 15.7mcg | 29% |
| Folate | 25mcg | 6% |
| Thiamin (B1) | 0.1mg | 8% |
| Riboflavin (B2) | 0.2mg | 15% |
| Niacin (B3) | 3.3mg | 21% |
% Daily Values based on a 2,000 calorie diet (FDA reference).
Health Benefits of Granola Bars
Granola bars provide a convenient, portable energy source primarily from oats, which contain beta-glucan fiber. Beta-glucan has strong evidence for reducing LDL cholesterol and supporting stable post-meal blood glucose levels by slowing digestion.
Magnesium at 67mg per 100g supports over 300 enzyme reactions including ATP synthesis, muscle relaxation, and sleep quality. Potassium at 339mg contributes to cardiovascular health and muscle function. Vitamin E at 4.6mg per 100g acts as a fat-soluble antioxidant protecting cell membranes from oxidative stress, particularly important during intense exercise.
Selenium at 15.7mcg supports thyroid function and antioxidant enzyme activity. The nuts typically found in granola bars contribute healthy mono and polyunsaturated fats, though the high saturated fat (17.1g per 100g) suggests coconut oil or palm oil is often used as a binding fat.
For endurance athletes, granola bars provide a practical mid-workout or pre-workout snack with quick-release carbohydrates from the sugars plus sustained energy from oats. For anyone in a calorie deficit, they offer less satiety per calorie than high-protein alternatives due to the low protein-to-calorie ratio.
Dietary Considerations
Most granola bars are not suitable for keto diets at 54.1g of carbs per 100g. Many varieties are gluten-free if made with certified gluten-free oats, but standard oats may contain cross-contamination. Check the label. Most granola bars are vegetarian, and some are vegan if honey is not used as a sweetener. For weight loss, granola bars are problematic because they are calorie-dense (536 per 100g) with relatively low protein (9.6g per 100g), providing less satiety per calorie than protein bars or whole food alternatives. The high sugar and fat content means they function more as an energy snack than a diet food despite their health-food image.
Daily Intake (100g)
100g of granola bar provides 27% of a 2,000-calorie diet.
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Frequently Asked Questions
How many calories in a granola bar?
A 1 oz granola bar (28g) has about 152 calories. Per 100g, granola bars contain 536 calories. Many standard bars sold in stores are 40-50g, putting a single bar at 215-268 calories.
Is a granola bar good for weight loss?
Granola bars are calorie-dense at 536 calories per 100g with only 9.6g of protein and 23.6g of sugar per 100g. They are not ideal for weight loss since they provide little satiety per calorie. A protein bar or handful of nuts with fewer sugars is a better option.
How much protein in a granola bar?
Granola bars contain 9.6g of protein per 100g and about 2.7g per 1 oz serving. This is much lower than protein bars (which average 20-30g per bar). If protein is the goal, granola bars are not the right snack.
Are granola bars high in sugar?
Yes, most granola bars are high in sugar at 23.6g per 100g and 6.7g per 1 oz serving. The sugar comes from honey, corn syrup, or other sweeteners used to bind the bar. Look for bars with less than 8g of sugar per serving.
Are granola bars a good pre-workout snack?
Granola bars can work as a pre-workout snack due to their carbohydrate content providing quick energy. One bar 30-60 minutes before exercise is reasonable. For workouts over 60 minutes, the carbs help sustain energy, especially for endurance activities.
Are granola bars gluten-free?
Oats are naturally gluten-free, but standard oat products are often contaminated with wheat during processing. Granola bars made with certified gluten-free oats are safe for celiac individuals. Always check the label.
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