Pork belly: how much fat, and what the red meat studies say

In a randomized trial in 16 active adults, a post-exercise meal of high-fat pork with 20 g protein and 20.6 g fat produced about a third less muscle protein synthesis than the same protein from lean pork, measured over a single five-hour window. That is as close as the research gets to pork belly. The only study we found that names the cut is a Korean market survey, where fat level judged by eye explained what distributors preferred. The fat itself varies a lot. UK tables put raw belly, lean and fat, at 258 calories and 20.2 g fat per 3.5 oz (100 g). Six US samples sold with the skin on ran from about 31 to 42 g fat, and the two records differ by 44 percent because the cut and the trim differ. The health findings below come from pork in general or from red meat as a whole.

The numbers, per 3.5 oz (100 g)

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

How much is actually in it

• UK tables list raw pork belly, lean and fat, at 258 calories, 20.2 g fat, 7.25 g saturated fat and 19.1 g protein per 3.5 oz (100 g). — food composition record, UK Evidence E source
  Per 100 g raw: energy 258 calories; fat 20.2 g; saturated fat 7.25 g; protein 19.1 g; water 61.7 g
• USDA Foundation samples of raw pork belly with skin ranged from about 31 to 42 g fat per 3.5 oz (100 g) across 6 samples. — USDA Foundation Foods analytic samples, raw pork belly with skin (n = 6) Evidence E source
  Fat 30.61-41.87 g per 3.5 oz (100 g) (reference value 35.83 g); protein 12.8-16.1 g; cholesterol 60.1-77.6 mg

What a real portion looks like

• The US dietary survey database counts one slice of pork belly as 30 g and an unspecified serving as 60 g. — FNDDS portion weights, US Evidence E source
  1 slice = 30 g; quantity not specified = 60 g; 1 cup = 135 g; 1 cubic inch = 17 g

What your body absorbs

• In a randomized trial in 16 active adults, 20 g protein from high-fat pork (20.6 g fat) raised muscle protein synthesis after exercise about a third less than the same protein from low-fat pork. — 16 physically active adults, 12 men and 4 women; single post-exercise meal (n = 16) Evidence B source
  MPS 0.072 %/h (95% CI 0.057-0.087) high-fat pork vs 0.106 %/h (95% CI 0.088-0.118) low-fat pork; P = 0.030
• In a randomized crossover study in 14 adults, pork from UVB-exposed pigs raised blood vitamin D3 by up to 0.9 nmol/L, against 1.5 nmol/L for a supplement and 0.7 nmol/L for ordinary pork. — 14 healthy adults; acute 24-hour crossover (n = 14) Evidence B source
  Max change 25(OH)D3 +0.9 nmol/L UV pork, +1.5 nmol/L supplement, +0.7 nmol/L control pork

What cooking and storage change

• In UK tables, grilling pork belly drops water from 61.7 g to 48.6 g per 3.5 oz (100 g), so fat and calories per 3.5 oz (100 g) rise from 20.2 g and 258 calories to 23.4 g and 320 calories. — food composition records, UK, raw vs grilled vs roasted belly Evidence E source
  Raw 258 calories, fat 20.2 g; roasted 293 calories, fat 21.4 g; grilled 320 calories, fat 23.4 g per 3.5 oz (100 g)
• By the USDA retention table for fresh pork, broiling keeps about 65% of vitamin B6 and 70% of thiamin, while zinc and riboflavin are fully retained. — USDA retention factors, group Pork Products, method fresh broiled Evidence E source
  Retained: vitamin B6 65%; thiamin 70%; iron 80%; niacin 80%; vitamin B12 90%; zinc 100%; riboflavin 100%
• A meta-analysis and risk model for China estimated Salmonella in about 8% of live pigs and linked reduced kitchen cross-contamination to lower infection risk from pork. — Chinese pig farms; farm-to-consumption risk model Evidence C source
  Salmonella prevalence 8.1% (95% CI 5.43-11.91%) in live pigs; about 3.46 million modeled annual cases

What it does to your health

• A meta-analysis of 19 cohorts with over 4.2 million people linked the highest total red meat intake to a 12% higher pancreatic cancer risk, but not processed or unprocessed red meat alone. — 19 prospective cohorts, 4,291,065 participants, 13,820 cases (n = 4291065) Evidence C source
  Total red meat HR 1.12 (95% CI 1.01-1.24); unprocessed HR 1.05 (0.88-1.24); processed HR 1.02 (0.86-1.21)

Safety, limits and interactions

• USDA FSIS advises cooking raw pork steaks, chops and roasts to at least 145 °F (63 °C) and letting the meat rest for at least three minutes before carving or eating. — consumers cooking whole cuts of pork, USA Evidence E source
  145 °F plus a 3-minute rest

Who this works differently for

• A meta-analysis of 10 intervention studies with 397 adults found eating more red meat raised hemoglobin by about 2.4 g/L but did not significantly change serum ferritin. — adults 18-70 years, 10 controlled intervention studies, 397 participants (n = 397) Evidence B source
  Hb +2.36 g/L (95% CI 0.71 to 4.02); ferritin +1.87 ug/L (95% CI -0.73 to 4.48), not significant
• A meta-analysis of 15 studies with 1162 people with alpha-gal syndrome found symptoms usually start an hour or more after eating red meat such as pork. — 1162 alpha-gal syndrome patients from 15 studies (n = 1162) Evidence C source
  Onset >= 1 h after red meat in 91.8% (CI 84.6-96.8); urticaria 63.8%; any GI symptom 69.2%

What is still unknown

• The only study naming pork belly in the corpus is a Korean market survey where fat level judged by eye, not measured fat percentage, explained distributor preference. — Korean pork distributors, four types Evidence C source
  Visual fat level R2 >= 0.75; measured fat percentage R2 < 0.2

The bottom line

Grilling concentrates what is there. In UK tables water falls from 61.7 g to 48.6 g per 3.5 oz (100 g), so grilled belly reads 23.4 g fat and 320 calories, with the caveat that raw and grilled figures come from different samples. A US survey slice weighs 1.1 oz (30 g) and an unspecified serving 2.1 oz (60 g). The USDA retention factor for broiled fresh pork keeps about 65 percent of vitamin B6 and 70 percent of thiamin, and all of the zinc and riboflavin. That is a group figure from a 1975 table, never measured on belly. A meta-analysis of 10 intervention studies in 397 adults found that eating more red meat raised hemoglobin by 2.36 g/L (95% CI 0.71 to 4.02). Ferritin, the measure of iron stores, did not change significantly. Not every included study was randomized, and none tested belly. Pork from pigs kept under UVB light lifted blood vitamin D3 by at most 0.9 nmol/L over 24 hours in a crossover trial in 14 adults, against 1.5 nmol/L for a supplement. That pork was specially produced, and ordinary pork managed 0.7 nmol/L. Observational data from 19 cohorts with 4.29 million people link the highest total red meat intake to a 12 percent higher risk of pancreatic cancer (HR 1.12, 95% CI 1.01 to 1.24). This is an association. Pork was not analyzed on its own, and neither processed nor unprocessed red meat reached significance separately. Who should be careful. People with alpha-gal syndrome react to red meat, pork included. In a meta-analysis of 1162 patients from 15 observational series, 91.8 percent had symptoms start an hour or more after eating, though the studies differed widely. Raw pork can carry Salmonella. A risk model for China estimated it in 8.1 percent of live pigs and found that less cross-contamination in home kitchens lowered the risk, a result nobody has checked for other countries. USDA FSIS advises cooking raw pork steaks, chops and roasts to at least 145 °F (63 °C) and letting the meat rest for at least three minutes before carving or eating. We have no card on pregnancy, children or medicines for pork belly.

Sources

1. pbl-r6-01 · food composition dataset
   CoFID 18-557 Pork, belly joint/slices, raw, lean and fat (group MAG): Energy 258 kcal; Fat 20.2 g; Satd FA 7.25 g; Protein 19.1 g; Water 61.7 g
   CoFID 2021 (Public Health England), code 18-557 Pork, belly joint/slices, raw, lean and fat · checked 2026-09-29
2. pbl-r6-02 · food composition dataset
   Pork, belly, with skin, raw (FDC 2727576, foundation, Pork Products): fat 35.83 g per 100 g, Foundation samples 30.61-41.87 n=6; protein 15.2 g, samples 12.844-16.081; cholesterol 66.62 mg, samples 60.1-77.6 n=6
   USDA FoodData Central Foundation Foods, FDC 2727576 Pork, belly, with skin, raw · checked 2026-09-29
3. pbl-r6-05 · portion dataset
   Pork, belly | FNDDS 22708020 | fdc_id 2705901 | 1 slice, any size 30 g | 1 oz yields 20 g | 1 cubic inch 17 g | 1 cup 135 g | Quantity not specified 60 g
   USDA FNDDS, Pork, belly, food code 22708020 (fdc_id 2705901) · checked 2026-09-29
4. pbl-r6-06 · randomized controlled trial
   Following exercise, participants ingested either HFP (266 kcal, 20 g protein, 20.6 g fat), LFP (120 kcal, 20 g protein, 4.4 g fat), or CHO (266 kcal, 0 g protein, 0 g fat, 73.3 g carbohydrate). ... with LFP eliciting a greater postexercise MPS {0.106 ± 0.026 %/h [95% confidence interval (CI): 0.088, 0.118]} than HFP [0.072 ± 0.027 %/h (95% CI: 0.057, 0.087); P = 0.030]
   Am J Clin Nutr, 2025 · checked 2026-09-29
5. pbl-r6-08 · randomized crossover trial
   UV pork and supplement significantly increased within-group serum 25(OH)D3 concentrations over timepoints (p < 0.05) (max. change 0.9 nmol/L (2.2%) UV pork, 1.5 nmol/L (3.5%) supplement, 0.7 nmol/L (1.9%) control).
   Int J Food Sci Nutr, 2023 · checked 2026-09-29
6. pbl-r6-03 · food composition dataset
   CoFID 18-557 raw: Energy 258 kcal; Fat 20.2 g; Water 61.7 g || CoFID 18-555 roasted: Energy 293 kcal; Fat 21.4 g; Water 55.8 g || CoFID 18-556 grilled: Energy 320 kcal; Fat 23.4 g; Water 48.6 g
   CoFID 2021 (Public Health England), codes 18-557, 18-555, 18-556 · checked 2026-09-29
7. pbl-r6-04 · retention dataset
   USDA-RETN-R6:1251 PORK,FRESH,BROILED | Pork Products (10) | vitamin_b6_mg 65% | thiamin_mg 70% | iron_mg 80% | niacin_mg 80% | vitamin_b12_ug 90% | zinc_mg 100% | riboflavin_mg 100%
   USDA Table of Nutrient Retention Factors, Release 6 (2007), Retn_Code 1251 PORK,FRESH,BROILED · checked 2026-09-29
8. pbl-r6-10 · meta-analysis and risk model
   The model estimated an overall Salmonella prevalence of 8.1% (95% CI: 5.43-11.91%) in live pigs and 13.29% (95% CI: 9.19-18.69%) in pig feces. ... Optimization of interventions at critical control points, such as using disinfectants during washing and reducing cross-contamination in household kitchens, can effectively reduce the risk of Salmonella contamination.
   Food Res Int, 2026 · checked 2026-09-29
9. pbl-r6-11 · meta-analysis of cohorts
   19 studies involving 4,291,065 participants with 13,820 pancreatic cancer cases were included. The highest intake of total red meat was positively related to risk of pancreatic cancer (Pooled HR: 1.12, 95%CIs: 1.01, 1.24; I2: 36.5 %, PQ-test: 0.10). Such association was not significant for unprocessed (Pooled HR: 1.05, 95%CIs: 0.88, 1.24; I2: 66.6 %, PQ-test: 0.002) and processed (Pooled HR: 1.02, 95%CIs: 0.86, 1.21; I2: 66.0 %, PQ-test: 0.001) red meat intake.
   Clin Nutr ESPEN, 2025 · checked 2026-09-29
10. sf-fsis5-7 · agency advice
    Cook all raw beef, pork, lamb, and veal steaks, chops, and roasts to a minimum internal temperature of 145 °F...For safety and quality, allow meat to rest for at least three minutes before carving or consuming.
    USDA FSIS, Doneness Versus Safety · checked 2026-10-08
11. pbl-r6-07 · meta-analysis of intervention studies
    Interventions involving increasing red meat intake had no significant effect on serum ferritin concentrations (raw mean change difference [RMCD] = 1.87 μg L-1; 95% CI, -0.73 to 4.48; t = 1.619; P = .139) but did have a positive effect on Hb concentrations (RMCD = 2.36 g L-1; 95% CI, 0.71 to 4.02; t = 3.297; P = .011).
    Nutr Rev, 2025 · checked 2026-09-29
12. pbl-r6-09 · meta-analysis
    Tick bite history was recalled by 78.7% (CI: 46.4-98.1; I2 = 99.1%), and 91.8% (CI: 84.6-96.8; I2 = 70.3%) had symptom onset ≥ 1 h post red meat intake.
    Neurogastroenterol Motil, 2026 · checked 2026-09-29
13. pbl-r6-12 · cross-sectional study
    The regression equations between appearance-based belly fat level and distributors' pork belly preferences demonstrated that all regression equations exhibited an R2 value of 0.75 or higher, indicating that appearance-based belly fat level can effectively explain distributors' pork belly preferences.
    Meat Sci, 2025 · checked 2026-09-29