Ratatouille: the oil and the salt are your choice

We found no study of ratatouille as a dish, so the evidence here comes from its parts, and the best of it is small. In a randomized crossover trial in 7 adults, salads of spinach, lettuce, cherry tomatoes and carrots eaten with fat-free dressing gave essentially no carotenoid absorption, and 6 g and then 0.99 oz (28 g) of canola oil raised it step by step. That was raw salad, so carrying it over to stewed vegetables is our inference. In a second crossover trial in 11 healthy volunteers, blood lycopene rose only when 26 oz (750 g) of unheated tomato juice came with refined olive oil, peaking at 24 hours, and the abstract gives no size for the rise. Oil also sets the calories. A US cup of 215 g has about 144 calories and 10.2 g fat, while the UK homemade recipe lists 7.0 g fat per 3.5 oz (100 g), and both depend on how much oil the cook pours.

Every statement here is tied to a source. The badge says what kind of evidence stands behind it: A is a meta-analysis or systematic review, E is the position of an expert body without its own analysis. How we verify →

As people eat it, per 3.5 oz (100 g)

As eaten	kcal	Protein	Fat	Carbs	Fiber
Ratatouille	67	1.09 g	4.73 g	5.77 g	1.9 g

USDA Food and Nutrient Database for Dietary Studies (FNDDS, release 2024-10-31): ratatouille as it is prepared and served, from the recipes behind the national dietary survey, rather than a single laboratory sample.

How much is actually in it

UK tables list homemade ratatouille at 82 calories, 7.0 g fat, 273 mg potassium and only 3 mg sodium per 3.5 oz (100 g), so most sodium in ratatouille comes from added salt. — UK food composition table record Evidence E source
Per 100 g: 82 calories, fat 7.0 g, protein 1.2 g, total sugars 3.3 g, fiber (NSP) 1.7 g, potassium 273 mg, sodium 3 mg; US FNDDS sodium 151 mg

What a real portion looks like

A cup (215 g) of ratatouille provides about 144 calories, 10.2 g fat, 4.1 g fiber, 40 mg vitamin C, 471 mg potassium and 325 mg sodium. — US dietary survey food record Evidence E source
Per 100 g: 67 calories, fat 4.73 g, fiber 1.9 g, vitamin C 18.7 mg, potassium 219 mg, sodium 151 mg

What your body absorbs

In a randomized crossover trial in 11 adults, drinking 26 oz (750 g) of tomato juice with olive oil raised all forms of blood lycopene, peaking at 24 hours, unlike the same juice without oil. — 11 healthy volunteers, single 26 oz (750 g) serving of unheated tomato juice with or without 10% refined olive oil (n = 11) Evidence B source
All lycopene isomers rose significantly only with oil; LDL and total cholesterol fell 6 h after the oil drink
In a randomized crossover trial in 7 adults, vegetable salads with fat-free dressing gave almost no carotenoid absorption, while 6 g and then 0.99 oz (28 g) of oil raised it step by step. — 7 adults, single salads of spinach, lettuce, cherry tomatoes and carrots with 0, 6 or 28 g canola oil (n = 7) Evidence B source
Chylomicron carotenoids negligible with 0 g oil; higher with 6 g (P < 0.04); higher again with 28 g (P < 0.02)

What cooking and storage change

In 12 obese insulin-resistant women, a meal of zucchini and pasta fried in 25 g extra-virgin olive oil gave lower insulin and C-peptide over 3 hours than grilled zucchini with the same oil raw. — 12 obese insulin-resistant women and 5 lean women, single meals with 150 g zucchini and 60 g pasta (n = 17) Evidence B source
C-peptide AUC lower after fried meal at 120, 150 and 180 min (P = .002 to .004) in obese women; no difference in lean women
In an uncontrolled trial in 22 healthy men, one 8.5 oz (240 g) serving of tomato sofrito cooked in olive oil was followed by lower CRP and TNF-alpha, which only suggests an effect. — 22 healthy men, single dose of sofrito 240 g per 70 kg after 3 days without tomato products (n = 22) Evidence C source
CRP fell (p = 0.010), TNF-alpha fell (p = 0.011)

What it does to your health

In a 12-week placebo-controlled trial in 100 stressed adults with high-normal or grade 1 blood pressure, 1.2 g a day of eggplant powder lowered clinic blood pressure. — 100 stressed adults with high-normal BP or grade 1 hypertension, 12 weeks (n = 100) Evidence B source
Diastolic BP lower at week 8, systolic and diastolic lower at week 12 vs placebo (size not given in abstract)

What people believe that the data does not support

The EU rejected a claim that lycopene helps keep the heart and arteries healthy, and none of 28 lycopene claims in the register is authorized. — EU food labeling Evidence E source
Non-authorized; 0 of 28 lycopene claims authorized

The bottom line

Salt is the other thing you control. The US record, a recipe with salt, gives 325 mg of sodium per cup, scaled from its per 3.5 oz (100 g) figure. The UK homemade recipe has no added salt and lists 3 mg per 3.5 oz (100 g). The same US cup has about 471 mg potassium and 40 mg vitamin C. Frying has one small trial behind it. In 12 obese insulin-resistant women, a meal of zucchini deep-fried and pasta stir-fried in 25 g extra-virgin olive oil gave lower insulin and C-peptide over 3 hours than grilled zucchini with the same oil raw, and the 5 lean women tested showed no difference. That was one meal, and the zucchini were deep-fried, which is not how ratatouille is cooked. A single-arm trial in 22 healthy men found lower CRP and TNF-alpha after one 8.5 oz (240 g) serving of tomato sofrito, with no control group, so it only hints at an effect. The blood pressure result for eggplant came from capsules. In a 12-week placebo-controlled trial in 100 stressed adults with high-normal or grade 1 blood pressure, 1.2 g a day of eggplant powder was reported to lower clinic pressure, and our card holds no size for the drop. It tells you nothing about a bowl of stewed eggplant. The EU rejected a claim that lycopene keeps the heart and arteries healthy, and none of the 28 lycopene claims in its register is authorized, which means the evidence fell short when it was assessed. We hold no card on allergy, pregnancy, children or medicines for this dish, so this page has no caution section, and that is a gap in our evidence.

Sources

rtt-daily-r5-02 · food composition dataset
Ratatouille, homemade | CoFID 15-659 | Energy 82 kcal | Fat 7.0 g | Protein 1.2 g | Total sugars 3.3 g | NSP 1.7 g | Potassium 273 mg | Sodium 3 mg | Water 84.7 g
CoFID 2021, Public Health England, Ratatouille, homemade (15-659), OGL v3.0 · checked 2026-10-01
rtt-daily-r5-01 · food composition dataset
Ratatouille | FNDDS code 75316050 | fdc_id 2710028 | 1 cup 10205 = 215 g | Quantity not specified 90000 = 108 g | per 100 g: Energy 67 kcal, Total lipid 4.73 g, Fiber 1.9 g, Vitamin C 18.7 mg, Potassium 219 mg, Sodium 151 mg
USDA FNDDS 2021-2023, Ratatouille, food code 75316050, fdc_id 2710028 · checked 2026-10-01
rtt-daily-r5-03 · crossover RCT
In a randomized, controlled, crossover feeding trial, eleven healthy volunteers were assigned to receive a single ingestion of 750g of tomato juice (TJ) containing 10% of refined olive oil/70kg body weight (BW) and 750g of TJ without oil/70kg BW on two different days. All lycopene isomers increased significantly in subjects consuming TJ with oil, reaching the maximum concentration at 24h.
Food Chem, 2015 · checked 2026-10-01
rtt-daily-r5-04 · crossover RCT
Essentially no absorption of carotenoids was observed when salads with fat-free salad dressing were consumed. A substantially greater absorption of carotenoids was observed when salads were consumed with full-fat than with reduced-fat salad dressing.
Am J Clin Nutr, 2004 · checked 2026-10-01
rtt-daily-r5-05 · crossover RCT
Meal A was composed of 60 g of pasta made from wheat flour and 150 g of grilled courgettes with 25 g of uncooked oil. Meal B included 15 g of oil in the 150 g of deep-fried courgettes and 10 g of oil in the 60 g of stir-fried pasta. ... This study demonstrated that in obese, insulin-resistant women, food fried in extra-virgin olive oil significantly reduced both insulin and C-peptide responses after a meal.
J Med Food, 2011 · checked 2026-10-01
rtt-daily-r5-06 · uncontrolled trial
In a clinical trial, 22 healthy male subjects consumed a single dose of sofrito (240 g/70 kg) after three days without ingesting any tomato products and following a low-antioxidant diet the day before the intervention.
Nutrients, 2019 · checked 2026-10-01
rtt-daily-r5-07 · RCT
Participants in the eggplant group ingested capsules containing eggplant powder (1.2 g/day; 2.3 mg of ACh/day) for 12 weeks, whereas participants in the placebo group ingested placebo capsules.
Nutrients, 2019 · checked 2026-10-01
rtt-daily-r5-08 · rejected health claim
POL-HC-7529 Lycopene Helps to maintain a healthy heart/contributes to maintain a healthy cardiovascular system/contributes to protect the arteries from narrowing and hardening/contributes to keep the arteries healthy/helps to maintain a normal blood flow. Non-authorised
EU Register on nutrition and health claims, claim POL-HC-7529, snapshot 2026-09-21 · checked 2026-10-01

Review. Reviewed on 2026-10-01 for evidence level, dose and population context, and claims a reader could misread. Bioma Learn has no human medical reviewer at this time, and we say so rather than invent one. Methodology. This is information, not medical advice.