Bacon vs pork belly: close on fat, and the health data is about bacon

In a randomized crossover feeding study in 12 volunteers, compounds from wood smoke rose in urine 2 and 12 hours after they ate smoked meat such as bacon or hot dog. It is a marker that you ate smoked meat, and it says nothing about harm on its own. On the plate the two cuts are close. Grilled, UK tables give streaky bacon 337 calories and 26.9 g fat per 3.5 oz (100 g), against 320 calories and 23.4 g fat for pork belly slices, and the belly has more protein, 27.4 g against 23.8 g. Bacon carries 1,680 mg of sodium per 3.5 oz (100 g). Every health study on this page is about bacon or processed meat. We found no study of fresh pork belly as a food.

How much is actually in it

• A British dietary survey of 747 people found cured meats supplied 65% of dietary nitrite. — 747 people aged 15-74 in four regions of Great Britain (n = 747) Evidence C source
  Mean intake about 1.4 mg nitrite from food; cured meats 65% of nitrite intake
• Grilled, UK composition data give streaky bacon 337 calories, 26.9 g fat and 1,680 mg sodium per 3.5 oz (100 g), against 320 calories, 23.4 g fat and more protein (27.4 g vs 23.8 g) for pork belly slices. — — Evidence E source
  Per 100 g grilled: streaky bacon 337 calories, fat 26.9 g, sat fat 9.80 g, protein 23.8 g, sodium 1680 mg; pork belly 320 calories, fat 23.4 g, sat fat 8.23 g, protein 27.4 g
• Across 68 US restaurant samples of cooked bacon, saturated fat ranged from 7.84 to 17.5 g per 3.5 oz (100 g) around a median of 12.6 g, so one strip can differ twofold. — — (n = 68 samples) Evidence E source
  Saturated fat 12.6 g per 3.5 oz (100 g) (range 7.84-17.5, median 12.6); spread 77%

What your body absorbs

• In a randomized crossover feeding study, smoke compounds (syringol sulfates) rose in urine 2 and 12 hours after eating smoked meat such as bacon or hot dog. — 12 volunteers eating bacon, salami and hot dog on consecutive days; validation in 474 EPIC participants (n = 12 (intervention); 474 (validation)) Evidence B source
  Syringol sulfates increased at 2 and 12 h after smoked meat; ROC AUC 0.78-0.86 short-term, 0.74-0.79 habitual

What cooking and storage change

• US processor data found five raw, not-ready-to-eat bacon samples above 4-log CFU/g Clostridium perfringens, while no cooked sample exceeded 2-log. — Raw chicken, not-ready-to-eat bacon and over 6,000 cooked meat products from three US processors (n = 3,141 + 2,886 cooked products) Evidence C source
  5 raw bacon samples >4-log CFU/g; no cooked sample >2-log CFU/g
• By the USDA retention table for pork, broiling or frying bacon keeps only 45% of its thiamin, while zinc stays at 100% and sodium at 90%. — — Evidence E source
  Retained after broil/fry: thiamin 45%, calcium 75%, iron 80%, B6 80%, sodium 90%, B12 90%, zinc 100%

What it does to your health

• An umbrella review of prospective cohorts rated high-quality evidence linking two slices of bacon a day with about double the risk of type 2 diabetes (HR 2.07, 95% CI 1.40 to 3.05). — Meta-analyses of prospective observational studies on diet and type 2 diabetes incidence (n = 53 publications) Evidence C source
  Bacon per two slices/day HR 2.07 (1.40 to 3.05); processed meat per 50 g/day 1.37 (1.22 to 1.54)
• An umbrella analysis of 137 associations for gastric cancer found only two risk factors with strong epidemiologic evidence, and bacon was one of them. — 76 meta-analyses of observational studies on non-genetic gastric cancer risk factors (n = 76 meta-analyses, 137 associations) Evidence C source
  Bacon among 10 associations with strong evidence (2 risk factors: waist circumference and bacon); effect size not given in abstract

Who this works differently for

• In a randomized crossover trial in 25 adults, a hamburger meal with bacon raised blood glucose and insulin 44% more than an energy-matched salmon and rye meal, with a larger insulin gap at higher BMI. — 25 healthy normal-weight and overweight volunteers aged 21-39, single test meals (n = 25) Evidence B source
  Postprandial glucose and insulin increases 44% lower after the unconventional meal; insulin difference correlated with BMI (r = 0.538)

The bottom line

The strongest health signal is observational. An umbrella review of meta-analyses of prospective cohorts, 53 publications in all, rated the evidence high quality for a link between two slices of bacon a day and about double the risk of type 2 diabetes (HR 2.07, 95% CI 1.40 to 3.05). For processed meat the figure was 1.37 (1.22 to 1.54) per 50 g a day. These are associations, and there is no separate estimate for fresh belly. A second umbrella review of 76 meta-analyses covering 137 associations found strong evidence for only two gastric cancer risk factors, and bacon was one of them. The abstract gives no effect size, so we cannot say how large that risk is. One trial looked at a whole meal. In 25 adults aged 21 to 39 eating single test meals, the rise in glucose and insulin was 44% lower after an energy-matched salmon and rye meal than after a hamburger meal with bacon. Bacon was one part of that meal, so the effect cannot be pinned on it. The insulin gap grew with body mass index (r = 0.538). Cooking changes a few things. By the USDA retention table, broiling or frying bacon keeps 45% of its thiamin, 90% of its sodium and all of its zinc, from a 1975 factor for pork products as a group. Across 68 US restaurant samples, cooked bacon ran from 7.84 to 17.5 g saturated fat per 3.5 oz (100 g) around a median of 12.6 g, with the frying method unknown. Who should be careful. We have no card on pregnancy, children, allergy or medicines for either cut, and that gap is real. The cautions we do have come from curing and handling. Industry data from three US processors found five raw bacon samples above 4-log CFU/g of Clostridium perfringens while no cooked product passed 2-log, so bacon sold raw is meant to be cooked. A British survey of 747 people from 1987 found cured meats supplied 65% of dietary nitrite, so it may not reflect intake today.

Sources

1. bcpb-daily-r2-05 · dietary survey
   Vegetables contributed over 90% of the nitrate intake and cured meats 65% of the nitrite intake.
   Food Chem Toxicol, 1987 · checked 2026-09-29
2. bcpb-daily-r2-07 · reference dataset
   CoFID 2021 19-018 Bacon rashers, streaky, grilled: Energy 337 kcal, Fat 26.9 g, Satd FA 9.80 g, Protein 23.8 g, Sodium 1680 mg per 100 g; 18-556 Pork, belly joint/slices, grilled, lean and fat: Energy 320 kcal, Fat 23.4 g, Satd FA 8.23 g, Protein 27.4 g per 100 g
   CoFID 2021, Public Health England, OGL v3.0, codes 19-018 and 18-556 · checked 2026-09-29
3. bcpb-daily-r2-08 · reference dataset
   Pork, cured, bacon, cooked, restaurant: Fatty acids, total saturated 12.6 G, range 7.84-17.5 (median 12.6), samples 68, spread 77%
   USDA FoodData Central, Foundation Foods, release 2026-04-30, Pork, cured, bacon, cooked, restaurant · checked 2026-09-29
4. bcpb-daily-r2-01 · randomized crossover trial
   The same compounds present as sulfate esters in urine increased at 2 and 12 h after consumption of smoked meat products (hot dog, bacon) in the intervention study.
   Am J Clin Nutr, 2019 · checked 2026-09-29
5. bcpb-daily-r2-06 · prevalence study
   Although five bacon (not RTE) samples exceeded 4-log CFU/g C. perfringens, none of the cooked samples (regardless of process deviations association) exceeded 2-log CFU/g
   J Food Prot, 2026 · checked 2026-09-29
6. bcpb-daily-r2-09 · reference dataset
   USDA-RETN-R6:1456 BACON,BROILED/FRIED, group Pork Products: thiamin_mg 45% retained, calcium_mg 75%, iron_mg 80%, vitamin_b6_mg 80%, sodium_mg 90%, vitamin_b12_ug 90%, zinc_mg 100%
   USDA Table of Nutrient Retention Factors, Release 6, 2007, Retn_Code 1456 · checked 2026-09-29
7. bcpb-daily-r2-03 · umbrella review
   Quality of evidence was also high for the association for increased incidence of type 2 diabetes with higher intake of red meat (for an increment of 100 g/day, 1.17 (1.08 to 1.26)), processed meat (for an increment of 50 g/day, 1.37 (1.22 to 1.54)), bacon (per two slices/day, 2.07 (1.40 to 3.05)), and sugar sweetened beverages (for an increase of one serving/day, 1.26 (1.11 to 1.43)).
   BMJ, 2019 · checked 2026-09-29
8. bcpb-daily-r2-04 · umbrella review
   Only 10 associations had strong epidemiologic evidence, including 2 risk factors (waist circumference and bacon), and 8 protective factors
   Front Public Health, 2022 · checked 2026-09-29
9. bcpb-daily-r2-02 · randomized crossover trial
   Postprandial increases in glucose and insulin were 44% lower after the unconventional meal (P<0.001 and P = 0.003, respectively). The difference between meals in insulin response (that is, conventional meal higher than unconventional) correlated with body mass index (BMI) (r = 0.538, P = 0.006).
   Eur J Clin Nutr, 2012 · checked 2026-09-29