Lemon Calories & Nutrition Calculator

Lemon delivers 53mg vitamin C per 100g of flesh (59% DV) at just 29 kcal — giving it a vitamin-C-per-calorie ratio of 1.83mg/kcal. This beats orange (1.13mg/kcal at 47 kcal), grapefruit (1.03mg/kcal at 33 kcal), and lime (0.97mg/kcal at 30 kcal). Only guava (3.36mg/kcal) significantly surpasses lemon among fruits ^[1].

However, lemon is rarely eaten by the 100g. A medium lemon without peel (84g) has just 24 kcal and 44.5mg vitamin C (49% DV). A typical squeeze into water (juice of half a lemon, ~25ml) delivers only 9.7mg vitamin C (11% DV). The vitamin C advantage is theoretical unless consuming whole lemon segments.

For food journaling, distinguish between whole lemon (including pulp and membrane — 53mg/100g) and juice only (38.7mg/100g). The fiber-rich pulp and membrane between segments contain more vitamin C per gram than the juice. Most lemon use in cooking and beverages involves juice only.

A single lemon yields three nutritionally distinct products. Whole fruit (without peel): 29 kcal, 2.8g fiber, 53mg vitamin C per 100g. Juice: 22 kcal, 0.3g fiber, 38.7mg vitamin C per 100g. Zest (outer peel): approximately 47 kcal, 10.6g fiber, 129mg vitamin C per 100g — the most nutrient-dense part that is usually discarded ^[1].

The fiber difference is the starkest: whole lemon has 2.8g fiber per 100g (10% DV) versus juice at 0.3g — a 9x difference. This means adding lemon juice to water provides essentially zero fiber, while eating a whole lemon wedge (7g) provides a small but real 0.2g fiber along with its vitamin C.

Lemon zest contains the highest concentration of the essential oil d-limonene (approximately 65% of the oil), which gives lemon its distinctive aroma. Zest also has the highest vitamin C concentration of any part of the fruit. For food journaling, zest (typically 2-4g per recipe) adds negligible calories but measurable vitamin C.

Lemon contains just 2.5g sugar per 100g — among the lowest of all fruits. For comparison: orange has 9.4g, grape 15.5g, apple 10.4g, banana 12.2g, and mango 13.7g. Even lime, lemon's closest relative, has slightly more sugar at 1.7g per 100g (the lower number reflecting lime's even stronger acidity) ^[1].

The sour taste is not from lack of sugar but from the dominance of citric acid — lemon juice contains approximately 5-6g citric acid per 100ml (5-6%), making it the most acidic common fruit juice (pH 2.0-2.6). The citric acid overwhelms the sweetness perception, which is why lemon tastes extremely sour despite having some sugar.

For food journaling, lemon is effectively a zero-sugar addition to food and beverages at typical usage quantities. One tablespoon of juice (15g) has 0.36g sugar and 3.3 kcal — truly negligible. Even an entire lemon's juice (50g) has only 1.2g sugar and 11 kcal. Lemon can be tracked as a flavoring rather than a caloric ingredient.

Lemon's 0.6mg iron per 100g is surprisingly high for a citrus fruit — orange has 0.10mg, lime 0.60mg, grapefruit 0.08mg. Among fruits, only dried fruits (raisins 1.88mg, dates 0.90mg) and a few fresh fruits like blackberry (0.62mg) match or exceed lemon's iron content ^[1].

The iron in lemon is non-heme (plant-based), but it exists alongside 53mg vitamin C per 100g — and vitamin C is well-documented to enhance non-heme iron absorption. This means lemon's iron, while modest in absolute terms, exists in an optimal absorption context. One medium lemon (84g) provides 0.5mg iron with 44.5mg vitamin C.

For food journaling, the practical iron contribution from lemon is small since most people consume juice only (0.08mg iron per 100g juice — negligible). However, adding lemon juice to iron-rich foods (lentils, spinach) may enhance iron absorption from those foods — a preparation strategy rather than a direct iron source.

A tablespoon of lemon juice (15g) has 3.3 kcal. Juice of half a lemon (25g) = 5.5 kcal. Juice of a whole lemon (50g) = 11 kcal. One whole medium lemon without peel (84g, eaten as segments) = 24 kcal. A lemon wedge (7g) = 2 kcal ^[1].

At these quantities, lemon functions more as a condiment than a caloric food. The calories from lemon juice are negligible in virtually any context — a glass of lemon water (juice of half a lemon in 250ml water) has 5.5 kcal. The same serving with added honey (10g) jumps to 35.5 kcal, with the honey contributing 85% of the calories.

For food journaling, lemon juice can be safely excluded from calorie tracking at 1-2 tablespoon quantities without meaningful impact. Track lemon only when: (1) consuming whole lemon segments in quantity, (2) making large batches of lemonade with sugar, or (3) using preserved/pickled lemons where oil and salt add substantial calories and sodium.