Does spinach help with weight loss?

Nobody has tested it. We found no randomized trial and no systematic review of eating spinach to lose weight. The trials that do exist used thylakoids, a membrane extract concentrated from spinach leaves and sold as a powder. A 2025 meta-analysis of 5 trials found it cut hunger by 2.4 mm and raised fullness by 4.6 mm on a 100 mm rating scale. That analysis was about appetite, and it reports no weight result.

Unsettled. The extract does something small to appetite, and whether that turns into lost weight is still open. A 2020 systematic review of 8 randomized trials found every one of them reported less hunger, and called the effect on body measurements controversial. The one trial with a clear weight result enrolled 48 women with a specific hormonal condition, all on a diet.

What the trials found

The extract, thylakoids

The 2025 meta-analysis found hunger fell by 2.415 mm (95% CI 1.287 to 3.544) and fullness rose by 4.602 mm (95% CI 2.356 to 6.848) when thylakoids were taken with meals. On a 100 mm scale those are shifts of a few millimeters. We could not get the full text, so the doses and the number of people in those trials are missing here.

In a 12-week trial, 48 women with obesity and polycystic ovary syndrome went on a calorie-restricted diet and took 5 g a day of spinach thylakoids or 5 g of cornstarch. The thylakoid group lost 15 lb (6.97 kg) and the placebo group 7 lb (3.19 kg), with waist and fat mass falling more as well. The trial came from a single research group in Tabriz, and we found no repeat of it in other groups of people.

In a 2026 trial, 60 men with obesity were split into four groups for 12 weeks, with or without high-intensity training and with thylakoids or placebo. Between training with placebo and training with the extract, systemic metabolic markers did not differ significantly, and the abstract gives no separate weight figure. 27 percent of the men did not finish.

In a single-dose crossover trial in overweight women, thylakoids were taken before breakfast. The abstract links their effect on wanting and liking scores for food to eating less, and the amount the women ate did not change significantly.

Spinach as food

The only trial of spinach itself was a small meal test. Ten healthy men ate mixed meals with 150 g or 250 g of microwaved spinach added, and the larger portion raised satiety and lowered the rise in blood sugar over the next few hours. Ten men and one afternoon say nothing about weight over months.

In three US cohorts of 133,468 adults followed for up to 24 years, each extra daily serving of green leafy vegetables was linked with 0.52 lb less weight gain over 4 years (95% CI 0.22 to 0.83). That group counted spinach together with kale, chard, mustard greens and lettuce, and it gave no figure for spinach alone. It is an association, and people who eat more greens differ in other ways that the analysis cannot fully remove.

Who should be careful

Not for everyone. A weight-loss diet built on very large amounts of spinach and other greens has been linked with a rare kidney injury. A 51-year-old man with type 2 diabetes, gout and high blood pressure lost 79 lb (36 kg) in seven months with exercise and a diet built around six daily meals of spinach, kale, berries and nuts. He developed kidney failure, a biopsy showed oxalate crystals, and he needed dialysis. It is one case, and the biopsy also showed diabetic kidney disease. If you have kidney disease or have had kidney stones, a diet heavy in spinach is worth talking over with your doctor first.

Because of its vitamin K, a 2021 systematic review of 149 reports, mostly case reports, lists spinach among the foods that can change how warfarin works. For someone on warfarin the point is steadiness. A sudden jump in spinach as part of a new diet is a change to talk over with the clinician who sets the dose. We found no trial of spinach or thylakoids in pregnancy or in children, and no study of how the extract behaves alongside medicines.

What expert bodies say

We found no position from EFSA, the US National Institutes of Health or the World Health Organization on spinach or on thylakoids for weight loss, and no approved EU health claim for thylakoids in this search.

How we searched

What would change this answer

• Any randomized trial in which people eat spinach, as food, and are weighed months later. None exists in what we searched.
• A thylakoid trial with weight as its main outcome, run by a group outside the developers, in men and women without a special diagnosis. Nothing is registered on ClinicalTrials.gov.
• A spinach-specific estimate from the large cohorts, separate from the other leafy greens.

What spinach contains and the rest of its evidence is on the spinach page.

Sources

1. ev-spnwl-01 · Meta-analysis or systematic review · systematic review and dose- and time-response meta-analysis · n = —
   The meta-analysis also suggests a significant association between the combination of thylakoids with meals and reduced hunger (WMD: -2.415 mm; 95% CI: -3.544, -1.287; P < 0.001) and increased fullness (WMD: +4.602 mm; 95% CI: 2.356, 6.848; P < 0.001).
   
   Who: adults in trials of thylakoid supplementation measuring hunger and fullness on visual analog scales, searched to May 2023
   Effect: hunger WMD -2.415 mm (95% CI -3.544 to -1.287); fullness WMD +4.602 mm (95% CI 2.356 to 6.848)
   Certainty: Thylakoid membrane extract, not whole spinach; weight was not an endpoint; a shift of a few mm out of 100 is small. No full text in PMC.
   Nutr Rev, 2025 · checked 2026-10-07 · we read the abstract
2. ev-spnwl-02 · Meta-analysis or systematic review · systematic review of RCTs without meta-analysis · n = —
   All studies supported this hypothesis that thylakoids reduce the feeling of hunger by increasing postprandial cholecystokinin and leptin and decreasing serum ghrelin, but the consequences of thylakoid intake on anthropometric characteristics were controversial.
   
   Who: humans in randomized clinical trials of thylakoid or chloroplast intake, 1990 to May 2019
   Effect: appetite lower in all trials; anthropometric effects controversial; no pooled estimate
   Certainty: Outside the corpus snapshot; qualitative synthesis without a number; the authors state directly that long-term data on weight are lacking.
   Journal of Diabetes and Metabolic Disorders, 2020 (systematic review of thylakoid intake, appetite and weight loss) · checked 2026-10-07 · we read the abstract
3. ev-spnwl-03 · Randomized controlled trial(s) · double-blind placebo-controlled randomized clinical trial · n = 48
   After the 12-week intervention, there were significant decreases in weight (- 6.97 ± 0.52 vs. -3.19 ± 0.72 kg; P < 0.001), waist circumference (- 7.78 ± 2.50 vs. -3.73 ± 1.40 cm; P < 0.001), fat mass (- 5.19 ± 0.53 vs. -1.36 ± 0.39 kg; P < 0.001), and insulin levels (- 5.40 ± 1.86 vs. -1.19 ± 0.85 μU/mL; P < 0.001) in the spinach-derived thylakoid group compared to the placebo group.
   
   Who: 48 females with obesity and polycystic ovary syndrome, 5 g/day thylakoid or 5 g/day cornstarch, with calorie-restricted diets, 12 weeks
   Effect: weight -6.97 ± 0.52 vs -3.19 ± 0.72 kg; waist -3.1 vs -1.5 in (-7.78 vs -3.73 cm); fat mass -11 vs -3 lb (-5.19 vs -1.36 kg) (all P < 0.001)
   Certainty: One research group (Tabriz), small sample, special population; the effect of an extract supplement, not of a serving of spinach.
   Nutr J, 2020 · checked 2026-10-07 · we read the abstract
4. ev-spnwl-04 · Randomized controlled trial(s) · randomized controlled trial, four arms, per-protocol and ITT · n = 60
   While no significant differences were observed between TPG and TSG for systemic metabolic markers, preliminary data suggested that thylakoid supplementation might provide modest complementary modulations in specific myokines (e.g., decorin and follistatin).
   
   Who: sixty men with obesity (age 27.6, BMI 32.6), four groups of 15: placebo, supplement, training + placebo, training + supplement, 12 weeks
   Effect: no significant differences between training + placebo and training + supplement in systemic metabolic markers; exercise drove body composition change
   Certainty: 27% attrition; no number for weight separately in the abstract.
   Nutrients, 2026 · checked 2026-10-07 · we read the abstract
5. ev-spnwl-05 · Randomized controlled trial(s) · randomized placebo-controlled crossover trial, single dose · n = —
   The treatment effect of thylakoids on scores for wanting and liking were correlated to a reduced intake by treatment (p < 0.01 respectively), even though food intake was not affected significantly.
   
   Who: overweight women given a single dose of thylakoid-rich spinach extract or placebo before breakfast
   Effect: hunger -21%, satiety +14%, cravings for sweet -38%; food intake not significantly affected
   Certainty: N not given in the abstract; single dose; the extract manufacturer (Lund University) is the developer.
   Appetite, 2015 · checked 2026-10-07 · we read the abstract
6. ev-spnwl-06 · Randomized controlled trial(s) · randomized crossover meal test · n = 10
   The largest spinach portions augmented satiety and reduced the postprandial glucose response.
   
   Who: ten healthy male volunteers; 150 g or 250 g microwaved spinach (4.3 or 7.2 g fiber) in 2000 kJ mixed meals
   Effect: largest spinach portion augmented satiety and reduced postprandial glucose; satiety tracked fiber and water content
   Certainty: Acute satiety over 3.5 h, not weight; 10 people.
   Int J Food Sci Nutr, 1995 · checked 2026-10-07 · we read the abstract
7. ev-spnwl-07 · Observational data · pooled analysis of three prospective cohorts · n = 133468
   Evaluating specific subgroups of vegetables, increased intakes of cruciferous and green leafy vegetables was inversely associated with weight change: pooled change -0.68 lb per daily serving of cruciferous vegetables (95% CI, 0.96 to -0.40 lb) and -0.52 lb per daily serving of green leafy vegetables (95% CI, -0.83 to -0.22 lb) (Fig 2).
   
   Who: 133,468 US men and women in three prospective cohorts, 1986 to 2010; green leafy vegetables = kale, mustard or chard greens, spinach, head or romaine lettuce
   Effect: -0.52 lb per daily serving over 4 years (95% CI -0.83 to -0.22)
   Certainty: Observational data, residual confounding; spinach was not assessed separately, only in the leafy green group.
   PLoS Med, 2015 · checked 2026-10-07 · we read the fulltext
8. ev-spnwl-08 · Laboratory or animal data · case report · n = 1
   Clinicians need to maintain a high index of suspicion for dietary hyperoxaluria as a potential etiology for acute or chronic kidney failure, particularly in patients pursuing intensive dietary weight loss intervention.
   
   Who: 51-year-old man with type 2 diabetes, gout, hypertension and morbid obesity; intensive dietary weight loss over 7 months
   Effect: end-stage renal failure (eGFR 4.4) with oxalate crystal deposition on biopsy; maintenance hemodialysis
   Certainty: A single case; diabetic nephropathy coexisted. Level D under the current rule for case series (pending Roman's decision).
   J Nephropathol, 2017 · checked 2026-10-07 · we read the abstract
9. ev-spnwl-09 · Observational data · systematic review of interaction reports, mostly case reports · n = —
   These include Chinese wolfberry, chamomile tea, cannabis, cranberry, chitosan, green tea, Ginkgo biloba, ginger, spinach, St. John's Wort, sushi and smoking tobacco.
   
   Who: reports of food, herbal or supplement interactions with warfarin, 5 databases to December 2019
   Effect: spinach named among foods to watch with warfarin (vitamin K)
   Certainty: No meta-analysis; the mechanism is vitamin K; the evidence is mostly from case reports.
   Br J Clin Pharmacol, 2021 · checked 2026-10-07 · we read the abstract
10. spn-dr-04 · Laboratory or animal data · systematic review of reported interactions between warfarin and food, herbs or dietary supplements across five databases from inception to 31 December 2019, classified by likelihood of interaction and supporting evidence · n = 149 reports
    These include Chinese wolfberry, chamomile tea, cannabis, cranberry, chitosan, green tea, Ginkgo biloba, ginger, spinach, St. John's Wort, sushi and smoking tobacco.
    
    Who: 149 articles describing 78 herbs, foods or dietary supplements
    Effect: 45 of the 78 items (57.7%) were reported to potentiate warfarin, 23 (29.5%) to inhibit it and 10 (12.8%) to have limited impact; 20 items were linked to bleeding events ranging from gum bleeding to fatal intracranial bleeding; spinach appears in the authors' list of items to be aware of
    Certainty: this is a review of case reports and small studies rather than trials, so it shows what has been reported and not how often it happens. The practical point for warfarin is consistency rather than avoidance: a steady amount of green vegetables is easier to dose against than a diet that swings. Anyone on warfarin decides this with the clinician who adjusts their dose, and not from a food page
    Br J Clin Pharmacol, 2021 · checked 2026-09-22 · we read the abstract