Banana: Macronutrient Profile
Per 100g, a ripe banana contains 89 kcal, 22.8g carbohydrates, 1.09g protein, 0.33g fat, and 2.6g dietary fiber (USDA FoodData Central). At stage 1 (unripe), carbs are primarily starch; at stage 6, primarily sugars.
The banana is nutritionally deceptive in its simplicity. 🍌 A medium ripe fruit looks like a snack, but its macronutrient composition shifts radically between harvest and full ripeness — making it effectively a different food at each end of the spectrum.
USDA Proximate Analysis: Ripe Banana Per 100g
The following values are from USDA FoodData Central (FDC ID 1105314), representing a stage 5–6 ripe raw banana:
| Macronutrient | Per 100g | % of Calories |
|---|---|---|
| Energy | 89 kcal | — |
| Water | 74.91g | — |
| Total Carbohydrates | 22.84g | 97% |
| Dietary Fiber | 2.60g | — |
| Total Sugars | 12.23g | — |
| Protein | 1.09g | 5% |
| Total Fat | 0.33g | 3% |
| Saturated Fat | 0.11g | — |
| Ash | 0.82g | — |
Bananas are overwhelmingly a carbohydrate food. At ~75% water by weight, they are also more hydrating than most people assume — only slightly drier than a strawberry (91% water) and considerably wetter than a dried date (21% water).
Starch vs Sugar Across Ripening Stages 1–7
The most dramatic macronutrient story in bananas is the starch-to-sugar conversion. An unripe green banana (stage 1) contains 20–25g resistant starch per 100g and under 2g total sugar. By stage 6, the enzymatic breakdown is near-complete:
| Stage | Description | Starch (g/100g) | Total Sugar (g/100g) | GI (approx.) |
|---|---|---|---|---|
| 1 | All green | 20–25 | < 2 | 30 |
| 2 | Green with yellow tip | 18–20 | 2–4 | 35 |
| 3 | More green than yellow | 14–18 | 4–7 | 42 |
| 4 | More yellow than green | 8–14 | 7–10 | 48 |
| 5 | Yellow with green tip | 4–8 | 10–13 | 52 |
| 6 | Full yellow | 1–4 | 12–15 | 58 |
| 7 | Yellow with brown spots | < 1 | 15–20 | 62 |
Glycemic index values are approximate and vary with individual physiology, cooking method, and co-ingested foods. The starch-rich stage 1 banana behaves metabolically more like a potato than a fruit.
Glycemic Load in Practice
Despite a moderate GI (around 52 for a stage-6 banana), the glycemic load of a medium banana (118g) is approximately 11, placing it in the low-to-medium GL category. Consumed with fat or protein, the effective blood sugar impact drops further — a practical reason the banana-with-peanut-butter pairing dominates sports nutrition.
Energy Density Comparison
Banana sits at the high end of fresh fruit energy density, but still well below calorie-dense foods:
| Fruit | Energy (kcal/100g) | Water (%) |
|---|---|---|
| Banana (ripe) | 89 | 75 |
| Apple | 52 | 86 |
| Mango | 60 | 83 |
| Grape | 67 | 81 |
| Avocado | 160 | 73 |
| Medjool date | 277 | 21 |
🍌 The banana’s energy density is driven almost entirely by its carbohydrate content — not fat or protein, which are both minimal. For a fruit with near-zero fat, achieving 89 kcal/100g is a testament to its concentrated sugar and starch profile, particularly in late-stage ripeness.
Protein Quality
At 1.09g protein per 100g, bananas are not a meaningful protein source. However, the amino acid profile includes all essential amino acids in trace quantities, with leucine (0.068g/100g), valine (0.047g/100g), and tryptophan (0.009g/100g) present. The tryptophan content, while small, has generated outsized public interest around the banana-mood connection — examined in detail in the micronutrients page.
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