Kraft Singles aren’t going to harm you in small amounts, but they’re far from a health food. Each slice is an ultra-processed product containing real cheese mixed with emulsifiers, preservatives, modified starch, and coloring agents. The bigger concern isn’t any single ingredient but the cumulative effect of regularly eating highly processed foods like this as dietary staples.
What’s Actually in a Kraft Single
The first ingredient is cheddar cheese (cultured milk, salt, enzymes), which sounds reassuring. But the slice also contains skim milk, whey, milkfat, milk protein concentrate, calcium phosphate, sodium phosphate, modified food starch, sorbic acid (a preservative), and coloring from paprika extract and annatto. That’s a long list for something that looks like a simple piece of cheese.
Legally, Kraft Singles can’t be labeled “cheese.” They’re classified as a “pasteurized prepared cheese product,” a distinct FDA category that allows for added moisture, emulsifiers, and other ingredients that wouldn’t be permitted in products simply labeled “cheese.” This isn’t a technicality. It reflects a genuinely different product from the block of cheddar in your fridge.
Nutrition Per Slice
One Kraft Single (19 grams) contains 50 calories, 3 grams of total fat (2 grams saturated), 3 grams of protein, and 210 milligrams of sodium, which is 9% of the recommended daily limit. It also delivers 290 milligrams of calcium, covering 20% of your daily needs. That calcium number is one of the genuine selling points, and it’s why the American Academy of Pediatrics once gave Kraft Singles a “Kids Eat Right” label.
For context, a comparable portion of natural cheddar cheese has roughly 7 grams of protein and about 5 grams of fat. So you’re getting significantly less protein per gram from a Kraft Single, while the sodium is higher than what you’d find in most unprocessed cheeses. If you’re eating Kraft Singles for the nutrition, you’d get more out of a smaller piece of real cheese.
The Sodium Problem
At 210 milligrams per slice, sodium adds up quickly. Two slices on a sandwich put you at nearly 20% of the daily recommended limit before you’ve counted the bread, condiments, or anything else on your plate. Most people already consume well above the recommended 2,300 milligrams per day, and processed cheese products are one of the quieter contributors because they don’t taste particularly salty. If you’re watching your blood pressure or managing heart health, this is one of the more practical reasons to limit Kraft Singles.
Phosphate Additives and Vascular Health
Kraft Singles contain both sodium phosphate and calcium phosphate, which act as emulsifiers to keep the cheese smooth and meltable. Phosphate additives are common across processed foods, and that’s part of the problem. Unlike the phosphorus naturally present in foods like meat, beans, and nuts, the inorganic phosphate in food additives is absorbed much more efficiently by your body, which can measurably raise phosphate levels in your blood.
Research published in Deutsches Ärzteblatt International found that elevated serum phosphate contributes to vascular damage, including stiffening of blood vessels and impaired blood vessel function. These effects have been observed in both animal studies and human subjects. A high-normal serum phosphate concentration has been identified as an independent predictor of cardiovascular events and mortality even in the general population, not just in people with kidney disease. The researchers concluded that the health impact of phosphate additives in food “may well have been underappreciated.”
A single Kraft slice isn’t going to cause vascular damage on its own. The concern is that phosphate additives are in so many processed foods that your total daily intake can climb well above what your body handles comfortably, especially if processed cheese, deli meats, and packaged meals are regular parts of your diet.
Ultra-Processed Food Effects
The Environmental Working Group classifies Kraft Singles as an “unhealthy ultra-processed food.” That classification matters because a growing body of research links regular ultra-processed food consumption to metabolic problems that go beyond any single nutrient on the label.
Ultra-processed foods tend to be low in fiber, which reduces your gut’s production of short-chain fatty acids. These fatty acids help maintain the intestinal barrier. Without enough of them, the gut becomes more permeable, allowing inflammatory compounds into circulation. Additives like emulsifiers and preservatives found in products like Kraft Singles are also associated with reduced diversity in gut bacteria, which plays a role in immune function and metabolic regulation.
Diets high in saturated fat from processed sources have been shown to trigger inflammatory responses that can blunt your body’s sensitivity to insulin and leptin, two hormones critical for blood sugar regulation and appetite control. Over time, this pattern contributes to insulin resistance, fatty liver disease, and cardiovascular problems. None of this happens from an occasional grilled cheese. It happens when ultra-processed foods become the default.
Sorbic Acid: A Preservative Worth Noting
Kraft Singles contain sorbic acid to prevent mold growth. It’s one of the most common food preservatives and is generally considered safe at approved levels. However, a 2022 study in the Journal of Food and Drug Analysis found that sorbic acid, even at concentrations below the average human intake level, caused fat to accumulate in the livers of mice over a four-week period. The mechanism involved disrupted fat metabolism: the preservative impaired the liver’s ability to break down and clear lipids while simultaneously increasing the production of triglycerides. Body weight and blood lipid levels didn’t change, meaning the liver effects were hidden.
This is a single animal study and doesn’t prove the same thing happens in humans. But the researchers specifically flagged that the doses used were below typical human consumption levels, suggesting this deserves more attention than it’s currently getting.
The Lactose Question
If you’re lactose intolerant, Kraft Singles are one processed food that might actually work in your favor. Most Kraft cheese products list “0g lactose per serving” on the packaging. The processing breaks down much of the lactose, though “0g per serving” technically means less than 0.5 grams rather than truly zero. For most people with lactose intolerance, this amount is well below the threshold that causes symptoms.
How It Compares to Real Cheese
Natural cheese like cheddar, Swiss, or gouda contains just a few ingredients: milk, salt, enzymes, and sometimes a bacterial culture. The protein content is higher per gram, the sodium is generally lower, and there are no emulsifiers, modified starches, or preservatives. You also get the same calcium benefit.
The tradeoff is convenience. Kraft Singles melt predictably, peel easily out of their wrappers, and last longer in the fridge. For a quick sandwich or a child’s lunch, they’re practical. But if you’re choosing between Kraft Singles and a slice of real cheese for nutritional value, real cheese wins on every metric except calcium density and cost.
If Kraft Singles show up in your diet occasionally, they’re not something to worry about. If they’re a daily fixture, the sodium, phosphate additives, and low nutritional return relative to real cheese make them worth swapping out for something less processed most of the time.