How Many Calories Are in a Slice of Bacon?

A single slice of regular-cut, pan-fried pork bacon contains roughly 43 calories. That number, drawn from standard nutritional databases for a cooked slice weighing about 8 grams, is the quick answer most people are looking for. But “a slice of bacon” is a surprisingly variable thing. The cut, the breed of pig, the curing method, and how long and hot you cook it can shift that number anywhere from the low 30s to well over 80 calories per slice. Understanding what drives that range turns out to be more interesting than the number itself.

Why One Slice Is Not Like Another

The biggest variable is thickness. A thin, center-cut slice that cooks down to a crispy strip weighs far less than a thick-cut piece from a fattier section of the belly. Thick-cut bacon slices can weigh two to three times as much as regular slices before cooking, and because more mass means more fat and protein left behind, they carry proportionally more calories. A thick-cut cooked slice can easily land between 60 and 90 calories.

The belly itself is not uniform. Research on pork bellies found that belly thickness has a direct linear effect on raw fat and water content, as well as the lean-to-fat ratio in the finished bacon. Thicker bellies tend to produce fattier slices with more calories per gram, while thinner bellies yield leaner bacon with a higher proportion of protein relative to fat.¹

Then there’s the breed of the pig. A study examining 182 pork bellies across different genotypes found dramatic variation in fat content. Standard commercial crossbreeds ranged from below 26% to above 34% fat, while pure Duroc pigs averaged around 47% fat, and Iberian-Duroc crosses reached an average of nearly 63% fat.² That is an enormous spread. Heritage and specialty breeds prized for flavor and marbling produce bellies with substantially more fat per gram, which translates directly into higher-calorie bacon. The artisanal thick-cut bacon from a heritage breed could contain double the calories of a thin-cut supermarket slice from a lean commercial pig.

What Happens When You Cook It

Raw bacon and cooked bacon are nutritionally different foods. A raw slice of regular-cut bacon contains roughly 10 to 12 grams of total weight, and a significant portion of that is water and rendered fat that leaves the slice during cooking. By the time bacon is done, a typical slice has lost about 40% or more of its starting weight.

Research on dry-frying temperatures confirmed what anyone who has cooked bacon suspects: higher temperatures cause greater cooking loss and lower moisture content in the finished product.³ What this means for calories depends on what leaves the slice. The rendered-out liquid is mostly fat and water. If you cook bacon until it is very crispy, more fat renders out, and the remaining slice is proportionally higher in protein and lower in fat per gram. But because the slice also weighs much less, the total calorie count per slice drops.

This is where preparation method matters in a practical sense. Bacon cooked on a rack in the oven lets fat drip away completely. Pan-fried bacon sits in some of its own fat and may reabsorb a portion. Microwave cooking tends to render fat efficiently and produces a result similar to oven-baked bacon. The calorie difference between methods for a single slice is modest, maybe 5 to 15 calories, but it adds up if you are eating several slices at a time.

Curing Method Changes the Numbers

Not all bacon is cured the same way, and the curing process affects both moisture content and calorie density. A study comparing different bacon preparations found meaningful nutritional differences across styles. Dry-cured bacon came in at roughly 190 to 197 calories per 100 grams, while brine-cured bacon was slightly lower at about 183 to 194 calories per 100 grams. Nitrite-free bacon, which typically uses celery powder or similar alternatives, was notably higher at 237 to 257 calories per 100 grams.⁴

The reason for the difference is largely about fat and protein proportions. The nitrite-free products in that study contained more fat per serving (13 to 15 grams per 100 grams compared to about 11.5 to 13 grams for traditionally cured varieties) and had substantially more protein (28 to 29 grams versus 18 to 21 grams). Brine-cured bacon tends to retain more water from the curing solution, which dilutes the calorie density by adding weight without adding energy.

For a single slice, these percentage differences are small in absolute terms. But if you are comparing brands at the grocery store and wondering why the calorie counts on two packages of bacon look different even at the same slice thickness, the curing method is often the explanation. “Uncured” or “nitrite-free” labels do not mean lower in calories; the opposite is often true.

Turkey Bacon, Canadian Bacon, and Other Alternatives

Turkey bacon is the most common substitute people reach for when they want lower-calorie bacon. A cooked slice of turkey bacon typically runs about 30 calories, roughly 25 to 30% fewer than regular pork bacon. The savings come from lower fat content, since turkey breast and thigh meat are leaner than pork belly. The tradeoff is texture and flavor: turkey bacon does not render the same way, does not crisp as well, and has a different mouthfeel that many people notice immediately.

Canadian bacon, which is actually back bacon cut from the loin rather than the belly, is leaner still. A slice of Canadian bacon contains roughly 30 to 40 calories, but slices tend to be thicker and meatier, making it feel more like a ham slice than what Americans picture as “bacon.” Because it comes from the loin, it has much less fat and more protein per gram than belly bacon.

Plant-based bacon alternatives have become increasingly visible. The same study that compared curing methods found that plant-based bacon rashers contained about 164 to 179 calories per 100 grams, the lowest of all the categories tested.⁴ However, the protein content was also the lowest, at about 9 to 12 grams per 100 grams compared to 18 to 29 grams for the meat-based options. A separate analysis of soy protein and seitan-based vegan bacon products found that these alternatives were generally low in fat, and seitan-based versions provided more protein than original pork bacon on a per-serving basis.⁵ So the calorie comparison with plant-based bacon depends heavily on the specific product and the protein source used.

Why Bacon Feels More Filling Than Its Calories Suggest

People frequently report that a few slices of bacon at breakfast keep them full longer than an equivalent number of calories from toast or cereal. There is a physiological basis for this. Bacon is a high-protein, high-fat food, and both of those macronutrients slow gastric emptying and promote satiety compared to carbohydrates.

Research on high-protein diets has found convincing evidence that higher protein intake increases both thermogenesis (the energy your body spends digesting food) and satiety compared to lower-protein meals. Higher-protein meals also tend to reduce how much people eat at subsequent meals.⁶ A study measuring diet-induced thermogenesis in a respiration chamber found that a high-protein diet burned about 14.6% of its energy during digestion, compared to roughly 10.5% for a high-fat diet, and that participants reported significantly higher satiety throughout the day on the higher-protein meals.⁷

Bacon is not a purely high-protein food; it delivers a roughly even split of calories from fat and protein. But compared to a piece of white toast, those 43 calories per slice pack a different physiological punch. The practical takeaway is that you cannot judge how filling a breakfast will be just by adding up total calories. Two slices of bacon at about 86 calories may hold you over longer than a 150-calorie bowl of cereal, though there are other nutritional factors in play.

The Sodium Question

Calories are not the only number people track with bacon. Sodium is often the bigger concern, especially for anyone watching blood pressure. A typical slice of cooked bacon contains around 130 to 190 milligrams of sodium, depending on the brand and cure. That adds up fast: three slices can deliver 400 to 570 milligrams, a significant chunk of the roughly 2,300 milligrams most dietary guidelines recommend as a daily limit.

The salt is there by design. Curing requires salt for both flavor and food safety. Research into salt reduction in cured meats has shown that it is technically feasible to cut salt in bacon products by about a third while still producing an acceptable product.⁸ But “acceptable” in a research setting does not always translate to what consumers will choose off the shelf. Lower-sodium bacon products exist and are worth seeking out if sodium is a priority, but they remain niche.

One thing to watch for: some brands reduce sodium per serving by simply defining a smaller serving size on the label. Always check the serving weight, not just the number of slices, when comparing products. A brand that lists one slice as a serving and another that lists two slices will give you dramatically different-looking nutrition panels even if the bacon inside is identical.

Processed Meat and Long-Term Health

The broader health conversation around bacon is not really about calories at all. In 2015, the International Agency for Research on Cancer classified processed meat as a Group 1 carcinogen, meaning there is sufficient evidence that it can cause cancer in humans. The specific concern is colorectal cancer, though stomach cancer has also been studied extensively.

A meta-analysis of studies on processed meat and stomach cancer found that for every additional 30 grams per day of processed meat consumed (roughly half an average serving), the relative risk of stomach cancer increased by about 15% in cohort studies. When the researchers looked specifically at bacon consumption, the finding was starker: those in the highest intake category had a roughly 37% higher relative risk of stomach cancer compared to those eating the least bacon.⁹ Relative risk percentages can sound alarming, but the baseline risk matters. Stomach cancer is relatively uncommon in Western countries, so a 37% increase on a small number is still a small number in absolute terms. That said, the consistency of the association across multiple studies is what gives the finding weight.

None of this means that a few slices of bacon at weekend brunch are a meaningful health risk for most people. The risk correlates with habitual, high-volume consumption over years. If you eat bacon a few times a month, the calorie content of each slice is probably a more relevant number for your daily decisions than the cancer epidemiology.

Reading Bacon Labels Without Getting Tricked

Grocery store bacon labeling is an exercise in creative presentation. Here are some things worth knowing when you are standing in the aisle comparing packages:

Center-cut: This means the fattiest ends of the belly have been trimmed off. Center-cut bacon has roughly 20 to 30% fewer calories per slice than regular bacon, and labels will usually say so prominently. It is one of the simplest ways to reduce calories without switching away from pork bacon entirely.
Uncured or no nitrites added: These products are still cured, typically with celery powder, which contains naturally occurring nitrites. As noted earlier, “uncured” bacon tends to be higher in both fat and calories than traditionally cured versions, so the label is not a signal of lower calorie content.
Thick-cut: Expect roughly 60 to 90 calories per cooked slice. Some brands do not adjust their “per slice” serving on the nutrition label to reflect the larger size, so you may need to weigh a slice or compare the total servings per package to get an honest number.
Low-sodium: Reduced salt does not change the calorie count meaningfully. If you are buying low-sodium bacon thinking it is also lower in calories, check the label again.

The nutrition facts panel is your best friend, but only if you pay attention to the serving size in grams rather than the number of slices. A “serving” of bacon varies from one to three slices depending on the brand and cut, and some companies deliberately use a one-slice serving to make the per-serving numbers look small.

How Breed and Feed Shape What Ends Up on Your Plate

If you buy bacon from a farmers’ market or a specialty butcher, you may notice that it tastes richer and fattier than supermarket bacon. This is not your imagination. As the pork belly research showed, breed is one of the most powerful determinants of fat content. Commercial crossbred pigs are bred for leanness, which keeps the fat content of their bellies under about 34%. Heritage breeds like Berkshire, Duroc, and Iberian crosses carry dramatically more intramuscular and subcutaneous fat.²

Feed plays a role too, though a smaller one than genetics. Pigs finished on acorns (as with Iberian ham traditions) or on high-energy grain diets tend to deposit more fat in the belly. The fat composition also changes: acorn-finished pigs have higher levels of oleic acid, the same monounsaturated fat found in olive oil, which affects both flavor and the melting behavior of the rendered fat.

For the calorie-conscious shopper, the practical point is that not all bacon is nutritionally interchangeable. A slice from a heritage-breed, thick-cut, dry-cured slab could deliver three times the calories of a thin-cut, center-cut slice from a lean commercial pig. Both are “one slice of bacon,” but they are not the same food in any meaningful nutritional sense. If precision matters to you, weighing your cooked bacon and using per-gram calorie data is far more accurate than counting slices.