Cheddar and mozzarella: melting the cheese moves the blood fats

In a 6-week randomized trial of 162 overweight adults aged 50 and over eating 4.2 oz (120 g) of full-fat cheddar a day, melted cheese raised total cholesterol by 7.7 mg/dL (0.20 mmol/L) and triglycerides by 15 mg/dL (0.17 mmol/L) more than unmelted cheese. Only cheddar was tested, so nobody has checked whether the same holds for mozzarella, which is mostly eaten melted. The fat behaves differently inside cheese than in butter. In a crossover trial of 19 adults with mildly raised cholesterol, 40 g of dairy fat a day for 4 weeks raised LDL cholesterol when eaten as butter and did not when eaten as mature cheddar. Cheese still is not neutral for LDL. In a 6-week feeding trial of 55 adults with high-normal blood pressure, a daily serving of a GABA-enriched cheddar raised LDL by 5.8 percent against a dairy-free diet and left blood pressure unchanged. Per 21 g slice in the US FNDDS database, cheddar gives about 86 calories and 7.1 g fat, and mozzarella about 62 calories and 4.3 g fat.

How much is actually in it

• In UK CoFID 2021, fresh mozzarella has about half the sodium and calcium of English cheddar (395 vs 723 mg sodium, 362 vs 739 mg calcium per 3.5 oz (100 g)), and both contain only trace lactose. — CoFID 2021 codes 12-346 and 12-360 Evidence E source
  Per 100 g cheddar vs fresh mozzarella: 416 vs 257 calories; sodium 723 vs 395 mg; calcium 739 vs 362 mg; lactose 0.1 g vs trace

What a real portion looks like

• A 21 g slice of cheddar gives about 86 calories, 4.9 g protein, 7.1 g fat, 137 mg sodium and 149 mg calcium in FNDDS. — FNDDS food code 14104100, Cheese, Cheddar Evidence E source
  Per 100 g: 409 calories, 23.3 g protein, 34 g fat, 654 mg sodium, 707 mg calcium
• A 21 g slice of mozzarella gives about 62 calories, 5.0 g protein, 4.3 g fat, 147 mg sodium and 146 mg calcium in FNDDS, so about 24 calories and 3 g fat less than cheddar. — FNDDS food code 14107010, Cheese, Mozzarella, NFS Evidence E source
  Per 100 g: 296 calories, 23.7 g protein, 20.4 g fat, 699 mg sodium, 693 mg calcium

What your body absorbs

• In a crossover RCT of 18 men, a cheddar meal produced a smaller 8-hour triglyceride rise than a fat- and protein-matched casein gel, by 21 mg/dL (0.24 mmol/L). — 25 normal-weight men aged 18-40 enrolled, 18 completed, single test meals (n = 18) Evidence B source
  Postprandial TG +21 mg/dL (0.24 mmol/L) after MCI gel vs cheddar (P <= 0.05); apoB-48 unchanged
• In a crossover trial of 24 young adults given 20 g protein as cheddar or milk, cheddar released branched-chain amino acids more slowly, peaking at about 120 minutes, with a smaller insulin response. — 24 adults (12 men, 12 women), about 27 years, single servings with 20 g protein (n = 24) Evidence B source
  BCAA peak about 120 min after cheese; insulin unchanged after cheese vs spike after milk

What cooking and storage change

• In a 6-week RCT of 162 overweight adults aged 50 and over eating 4.2 oz (120 g) cheddar daily, melted cheese raised total cholesterol by 7.7 mg/dL (0.20 mmol/L) and triglycerides by 15 mg/dL (0.17 mmol/L) more than unmelted cheese. — 162 overweight adults aged 50+, 120 g full-fat cheddar or equivalent components daily, 6 weeks (n = 162) Evidence B source
  Melted vs unmelted: total cholesterol +7.7 mg/dL (0.20 mmol/L), triglycerides +15 mg/dL (0.17 mmol/L); no HDL/LDL difference
• In a double-blind RCT of 96 adults, vitamin D3 in mozzarella baked on pizza stayed bioavailable, raising blood 25(OH)D by 73 nmol/L with 28,000 IU weekly for 8 weeks. — 96 healthy adults, fortified mozzarella on pizza once weekly, 8 weeks (n = 96) Evidence B source
  25(OH)D +73 nmol/L (high dose) vs +5.1 nmol/L (200 IU)

What it does to your health

• In a 3x2-week crossover RCT of 7 men eating 8.5 oz (240 g) cheddar a day, the high-calcium cheddar lowered fasting LDL cholesterol compared with reduced-calcium cheese, without changing fecal fat. — 7 healthy men, BMI 18-25, 240 g cheese daily, three 2-week periods (n = 7) Evidence B source
  Fasting LDL-C lower on high-calcium cheese (P = 0.002); fecal fat no difference (P = 0.066)
• In a 6-week crossover feeding RCT of 55 adults with high-normal blood pressure, one daily serving of GABA-enriched cheddar raised LDL cholesterol by 5.8% versus a dairy-free diet without changing blood pressure. — 55 healthy adults with high-normal daytime blood pressure, three 6-week isoenergetic diets (n = 55) Evidence B source
  LDL-C +5.8% vs control (P = 0.006); ambulatory systolic BP no difference (P = 0.34)
• In a 6-week crossover RCT of 30 adults with overweight, three dairy servings a day including full-fat cheddar did not change IL-6 but lowered TNF-alpha compared with a low-dairy diet. — 30 adults (18 women, 12 men) with overweight or obesity, 6 weeks per arm (n = 30) Evidence B source
  No change in IL-6 (primary); TNF-alpha decreased (P = 0.042), IL-4 increased (P = 0.026)

Safety, limits and interactions

• A meta-analysis of 16 studies estimated Listeria monocytogenes in 1.2% of mozzarella samples at the end of production, usually from contamination after stretching. — 16 studies of mozzarella samples, including 10 years of Italian laboratory data (n = 16) Evidence C source
  Pooled prevalence 1.2% (95% CI 0.0-4.2), I2 = 78%; levels below quantification
• Among four fatal choking cases in children aged 1.5 to 3 years, mozzarella cheese was one of the foods aspirated. — four fatal foreign body aspiration cases, children 1.5-3 years (n = 4) Evidence D source
  Mozzarella among 3 food items causing fatal aspiration
• The CDC lists large chunks of cheese among potential choking hazards for young children. — Infants and young children (n = -) Evidence E source
  Listed as food to avoid for young children (choking risk)
• For people at higher risk of Listeria, CDC lists mozzarella as a safer choice when it is made with pasteurized milk. — people at higher risk for Listeria: women who are pregnant, people 65 years or older, people with a weakened immune system Evidence E source
  String cheese, feta and mozzarella listed as a safer choice when made with pasteurized milk
• The FDA label for transdermal selegiline (EMSAM) at 9 mg/24 h or more lists aged cheeses as foods to avoid and mozzarella as acceptable. — Adults using EMSAM (selegiline transdermal system) at 9 mg/24 h or 12 mg/24 h (n = -) Evidence E source
  Aged cheeses: avoid; mozzarella: acceptable (label Table 5, dairy)

What people believe that the data does not support

• In a crossover RCT of 19 adults with mildly high cholesterol, 40 g dairy fat a day for 4 weeks as butter raised LDL, while the same fat as mature cheddar did not. — 14 men and 5 women, mean age 56, total cholesterol 217 mg/dL (5.6 mmol/L), 4 weeks per arm (n = 19) Evidence B source
  LDL-C median butter 3.9 vs cheese 3.7 vs run-in 131 mg/dL (3.4 mmol/L); in 13 with LDL >4: butter 4.4 vs cheese 3.9 (P = 0.014)

Who this works differently for

• In a crossover RCT of 58 adults, a cheese or yogurt snack cut later pizza intake by 175 calories against water, but older adults compensated for the snack's calories less than younger adults. — 30 adults aged 60-70 and 28 aged 20-30, single test sessions (n = 58) Evidence B source
  Pizza intake -175 calories after cheese or yogurt vs water; compensation 33% older vs 63% young

The bottom line

The two cheeses on this page are not the same product in every database. The FNDDS mozzarella is the firmer part-skim kind. Fresh mozzarella in the UK CoFID has 395 mg sodium and 362 mg calcium per 3.5 oz (100 g) against 723 mg and 739 mg for English cheddar, and both carry only a trace of lactose. Some of the cheddar effect looks tied to how cheese is built. In a crossover trial of 18 young men, a casein gel matched for fat and protein raised blood triglycerides over 8 hours by 21 mg/dL (0.24 mmol/L) more than a cheddar meal. In 24 young adults given 20 g of protein, cheddar released branched-chain amino acids more slowly than milk, peaking at about 120 minutes. A high-calcium cheddar lowered fasting LDL against a reduced-calcium cheese in a 2-week crossover trial of just 7 men eating 8.5 oz (240 g) a day, with heavy dropout. Three dairy servings a day that included cheddar did not change IL-6, the main outcome, in 30 adults with overweight over 6 weeks, and the effect of the cheese alone is unknown. Two trials used cheese as a vehicle. Mozzarella fortified with vitamin D3 and baked on pizza raised blood 25(OH)D by 73 nmol/L at 28,000 IU a week for 8 weeks in 96 adults. That vitamin D was added to the cheese, and ordinary mozzarella carries almost none. The 28,000 IU a week was a trial dose under study conditions, and we hold no card on the upper limit for vitamin D. In 58 adults, a cheese or yogurt snack cut later pizza intake by 175 calories against water, and older adults made up for the snack's calories less than younger ones, 33 against 63 percent. Who should be careful. A meta-analysis of 16 studies put Listeria monocytogenes in 1.2 percent of mozzarella samples (95% CI 0.0 to 4.2), with high variation between studies, mostly from contamination after the curd was stretched. That risk matters most for pregnant women and older adults. We hold no card yet on which mozzarella is safer for them, and that gap is not reassurance. Among four fatal choking cases in children aged 1.5 to 3 years, mozzarella was one of the foods inhaled, a case series that gives no rate and no advice on how to serve cheese to toddlers. We have not yet gathered evidence on tyramine in aged cheese such as mature cheddar with MAO-inhibitor drugs. The lack of a warning here does not mean there is nothing to warn about. If you take a medicine that comes with food warnings, which cheeses fit is a question for the person treating you.

Sources

1. chmz-daily-r8-03 · food composition dataset
   Cheese, Cheddar, English [12-346] Energy 416 kcal; Fat 34.9 g; Protein 25.4 g; Sodium 723 mg; Calcium 739 mg; Lactose 0.1 g per 100 g; Cheese, Mozzarella, fresh [12-360] Energy 257 kcal; Fat 20.3 g; Protein 18.6 g; Sodium 395 mg; Calcium 362 mg; Lactose Tr per 100 g
   CoFID 2021 (Public Health England), codes 12-346 Cheese, Cheddar, English and 12-360 Cheese, Mozzarella, fresh · checked 2026-10-02
2. chmz-daily-r8-01 · food composition dataset
   Cheese, Cheddar [2705709] Energy 409 KCAL; Protein 23.3 G; Total lipid (fat) 34 G; Sodium, Na 654 MG; Calcium, Ca 707 MG per 100 g; 1 slice 21 g
   USDA FNDDS 2021-2023, food code 14104100 Cheese, Cheddar (fdc_id 2705709) · checked 2026-10-02
3. chmz-daily-r8-02 · food composition dataset
   Cheese, Mozzarella, NFS [2705722] Energy 296 KCAL; Protein 23.7 G; Total lipid (fat) 20.4 G; Sodium, Na 699 MG; Calcium, Ca 693 MG per 100 g; 1 slice 21 g
   USDA FNDDS 2021-2023, food code 14107010 Cheese, Mozzarella, NFS (fdc_id 2705722) · checked 2026-10-02
4. chmz-daily-r8-07 · randomized crossover trial
   Postprandial triglycerides (TGs) (primary outcome) increased by (mean ± SEM) 0.24 ± 0.07 and 0.19 ± 0.07 mmol/L after MCI Gel compared with Cheese and Hom. Cheese, respectively (both P ≤ 0.05).
   Am J Clin Nutr, 2021 · checked 2026-10-02
5. chmz-daily-r8-08 · randomized crossover trial
   We found that cheese ingestion had a slower yet more sustained branched-chain amino acid circulation appearance over the postprandial period peaking at ~120 min.
   Nutrients, 2021 · checked 2026-10-02
6. chmz-daily-r8-04 · randomized controlled trial
   Melted cheese increased total cholesterol concentrations by 0.20 ± 0.15 mmol L-1 and triglyceride concentrations by 0.17 ± 0.08 mmol L-1 compared to unmelted cheese.
   Food Funct, 2024 · checked 2026-10-02
7. chmz-daily-r8-11 · randomized controlled trial
   Serum 25-hydroxyvitamin D increased by 5.1 ± 11 nmol/L in the low-dose group (n = 47; P = 0.003), and by 73 ± 22 nmol/L in the high-dose group (n = 49; P < 0.0001).
   Can J Diet Pract Res, 2015 · checked 2026-10-02
8. chmz-daily-r8-06 · randomized crossover trial
   Fasting LDL-c was significantly lower following the HCC diet vs. the other arms (P = 0.002).
   Eur J Nutr, 2023 · checked 2026-10-02
9. chmz-daily-r8-09 · randomized crossover trial
   The cheese diet increased serum LDL-cholesterol concentrations compared with the control and milk diets (+5.8%, P = 0.006 and +7.0%, P = 0.0008, respectively)
   Am J Clin Nutr, 2020 · checked 2026-10-02
10. chmz-daily-r8-14 · randomized crossover trial
    After controlling for age, BMI, sequence and period, there were no condition∗time interactions for interleukin-6 (IL-6; primary endpoint); however, there were condition∗time interactions for tumor necrosis factor-alpha (TNF-α; P = 0.042), and IL-4 (P = 0.026) such that they decreased and increased, respectively, on the HD diet compared with the LD diet.
    J Nutr, 2026 · checked 2026-10-02
11. chmz-daily-r8-12 · meta-analysis of prevalence studies
    In total, 16 studies were analyzed using random-effects meta-analysis, and the pooled prevalence of L. monocytogenes in mozzarella was estimated at 1.2% (95% CI: 0.0-4.2) although a high heterogeneity among studies was observed (I2 = 78%).
    J Dairy Sci, 2025 · checked 2026-10-02
12. chmz-daily-r8-13 · case series with mini-review
    In three cases, the foreign bodies were food (mozzarella cheese, pear, or raw bean), while in one case, the foreign body was a pebble.
    Int J Environ Res Public Health, 2020 · checked 2026-10-02
13. sf-choke-r2-2 · agency advice
    Large chunks of cheese, especially string cheese.
    CDC, Infant and Toddler Nutrition: Choking Hazards · checked 2026-10-08
14. sf-lsc-r3-cheddarmozz-1 · agency advice
    Cottage cheese, cream cheese, string cheese, feta, and mozzarella, when made with pasteurized milk
    Preventing Listeria Infection, Centers for Disease Control and Prevention, Safer Food Choices · checked 2026-10-08
15. sf-tymaoi-14 · agency advice
    Aged cheeses ... Processed cheeses, mozzarella, ricotta cheese, cottage cheese, and yogurt
    EMSAM (selegiline transdermal system), FDA-approved label, sections 2.3 and 7.2 (Table 5) · checked 2026-10-08
16. chmz-daily-r8-05 · randomized crossover trial
    A total of 40 g dairy fat eaten daily for 4 weeks as butter, but not as cheese, raised total and LDL cholesterol significantly compared with a diet containing significantly less saturated fat.
    Eur J Clin Nutr, 2005 · checked 2026-10-02
17. chmz-daily-r8-10 · randomized crossover trial
    Pizza intake was reduced by 175 kcal after yogurt and cheese and by 82 kcal after milks compared to water (P < 0.001). ... Compensation was less in older (33%) than in young (63%) adults (P < 0.03).
    J Nutr, 2021 · checked 2026-10-02