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Fruits

Lemon

Lemon is 89% water, so 100 g (3.5 oz) brings only 29 kcal and 2.8 g of fiber.

USDA description: Lemon, raw, without peel

  • Low energy density
  • Hydrating

Estimated satietyHow it is calculated

Starting point+1
Very low energy density: 29 kcal/100 g+2
Protein: 3.8 g/100 kcal0
Fiber: 9.7 g/100 kcal+2
Solid food with 89.0 g of water+1
Sum6
Capped at 55

Our own estimate from the values per 100 g: useful for comparing foods with each other, not a measurement in people. Holt index (1995): this food was not measured.

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Last updated
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Sources
9 primary
Data
USDA FDC 167746

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Nutrition facts

Calories
9 kcal per serving
29 kcal per 100 g (3.5 oz)
Protein
0.3 g per serving
1.1 g per 100 g (3.5 oz)
Carbohydrates
2.8 g per serving
9.3 g per 100 g (3.5 oz)
of which sugars
0.8 g per serving
2.5 g per 100 g (3.5 oz)
Fiber
0.8 g per serving
2.8 g per 100 g (3.5 oz)
Fat
0.1 g per serving
0.3 g per 100 g (3.5 oz)
of which saturated
0 g per serving
0 g per 100 g (3.5 oz)
Water
26.7 g per serving
89 g per 100 g (3.5 oz)

Source: USDA FoodData Central: Lemons, raw, without peel (FDC ID 167746), accessed September 23, 2026.

A typical 30 g (1 oz) serving provides about 9 kcal, 0.3 g of protein, and 0.8 g of fiber.

The typical serving (30 g (1 oz)) is a common amount used for the math, not a recommendation. Ounces and cups are rounded US equivalents; the values come from the database entry cited in the sources.

What it is and how to eat it

The lemon (Citrus limon) is the yellow, acidic citrus fruit used mainly for flavor; in Spain, Argentina, Chile and Uruguay it is the everyday limón. In Mexico and Central America, by contrast, limón usually means the green lime, which has its own page, and this fruit is called limón amarillo. This page covers the flesh without peel, with 29 kcal and 2.8 g of fiber per 100 g according to USDA; strained juice has 22 kcal and 0.3 g of fiber.

A 30 g (1.1 oz) serving of flesh, roughly half a lemon, provides about 9 kcal and 0.8 g of fiber, so it is used as a seasoning: its juice adds flavor to protein and vegetables with very few calories, as in the lemon chicken with sautéed vegetables or the chicken salad with apple, celery, and yogurt. The 2025 nutrition advisory on GLP-1 therapy suggests starting meals with protein, and lemon is a way to add flavor to it without adding fat. The US National Institutes of Health include citrus among the acidic foods that can make reflux worse, a common side effect of these medications according to the Wegovy label; if you get heartburn, especially in the first few days of treatment or after a dose increase, try less of it or use herbs and spices instead.

What the evidence says

The flesh has 53 mg of vitamin C per 100 g, more than the 24 mg the EU requires for a "high vitamin C" claim, so it could carry the authorized claim "vitamin C contributes to the normal function of the immune system" (Regulations (EC) No 1924/2006 and (EU) No 432/2012). What you actually take in is less: the 30 g serving provides 15.9 mg, 20% of the EU's 80 mg reference value, and the juice of one lemon, about 48 g according to USDA, 18.6 mg, 23% (Regulation (EU) No 1169/2011). The EU register lists as non-authorized the assessed claims that credited lemon with benefits for digestion or its flavonoids with an antioxidant effect. I have not found trials showing that lemon water, on an empty stomach or at any time, helps with weight loss.

The sources for this section are listed under "Sources" at the end of the page.

Satiety

The 1 to 5 score is our own estimate: it starts at 1 point, adds points for low energy density, for protein and fiber per 100 kcal, and for the water in solid foods, and subtracts points for drinks with calories. It is useful for comparing foods with each other; it is not a measurement in people.

What to keep in mind on a GLP-1 medication

Low energy density
It has 100 kcal or less per 100 g: plenty of volume for few calories, which helps you feel full. On a GLP-1 medication, which already reduces your appetite, make sure these foods do not push protein foods off your plate.
Hydrating
It has 85 g of water or more per 100 g, so it contributes to hydration. That helps because with a smaller appetite people also tend to eat and drink less, and not drinking enough can make constipation worse.

Frequently asked questions about lemon

How much protein does a 30 g (1 oz) serving of lemon have?

100 g (3.5 oz) of lemon has 1.1 g of protein. A typical 30 g (1 oz) serving has about 0.3 g of protein. That is 3.8 g of protein per 100 kcal.

How many calories are in a 30 g (1 oz) serving of lemon?

100 g (3.5 oz) of lemon has 29 kcal. A typical 30 g (1 oz) serving has about 9 kcal. That is a very low energy density.

How many grams of fiber are in a 30 g (1 oz) serving of lemon?

100 g (3.5 oz) of lemon has 2.8 g of fiber. A typical 30 g (1 oz) serving has about 0.8 g of fiber.

How filling is lemon?

Very filling for the calories it provides: our estimated satiety score is 5 out of 5. Calculation: 1 (base) + 2 (very low energy density: 29 kcal/100 g) + 0 (protein: 3.8 g/100 kcal) + 2 (fiber: 9.7 g/100 kcal) + 1 (solid food with 89.0 g of water) = 6; capped at 5. It is an estimate based on its composition, not a measurement in people.

Is lemon a good choice on a GLP-1 medication?

Based on our tags, this is what matters about lemon on a GLP-1 medication. “Low energy density”: plenty of volume for few calories; make sure it does not push protein foods off your plate. “Hydrating”: a lot of water, which contributes to hydration when you eat and drink less. These are general guidelines, not medical advice: everyone tolerates foods differently.

How many grams or ounces are in a serving of lemon?

We use 30 g (1 oz) as a typical serving. That amount provides about 9 kcal, 0.3 g of protein, and 0.8 g of fiber. It is a reference for calculations, not a recommendation of how much to eat.

See all foods

Sources

Sources for the data on this page, with the access date.

  1. Official databaseU.S. Department of Agriculture, Agricultural Research Service.USDA FoodData Central: Lemons, raw, without peel (FDC ID 167746).accessed .
  2. Official databaseU.S. Department of Agriculture, Agricultural Research Service.USDA FoodData Central: Lemon juice, raw (FDC ID 167747).accessed .
  3. Clinical guidelineObesity (Wiley).Mozaffarian D, et al. Nutritional priorities to support GLP-1 therapy for obesity: A joint Advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association, and The Obesity Society. Obesity. 2025;33(8):1475-1503. doi:10.1002/oby.24336.accessed .
  4. InstitutionNational Institute of Diabetes and Digestive and Kidney Diseases (NIH).Eating, Diet, & Nutrition for GER & GERD.accessed .
  5. Drug labelEuropean Medicines Agency.Wegovy (semaglutide): EU Summary of Product Characteristics, section 4.8 (undesirable effects), current version.accessed .
  6. RegulatorOfficial Journal of the European Union (EUR-Lex).Regulation (EC) No 1924/2006 on nutrition and health claims made on foods (Annex).accessed .
  7. RegulatorOfficial Journal of the European Union (EUR-Lex).Commission Regulation (EU) No 432/2012 establishing a list of permitted health claims made on foods.accessed .
  8. RegulatorOfficial Journal of the European Union (EUR-Lex).Regulation (EU) No 1169/2011 on the provision of food information to consumers (Annex XIII, nutrient reference values).accessed .
  9. RegulatorEuropean Commission.EU Register of nutrition and health claims made on foods.accessed .