Is a grilled cheese sandwich less healthy than a cold one? Food experts explain

The cheese melts and runs down the sides, the bread turns golden brown, and there's often a little butter sizzling in the pan. A grilled cheese sandwich certainly looks more indulgent than two ordinary slices of bread with cheese straight from the fridge.

But is it actually less healthy? According to nutrition experts, the answer is surprisingly simple.

There is, however, one difference worth knowing about. And you can see it in the color of the bread.

What happens when you heat bread and cheese?

When you put a cheese sandwich in a toastie maker or frying pan, several things happen. The bread loses some moisture and becomes crispier, while the cheese softens and its fat begins to melt.

That melted fat can make the sandwich look much greasier than its cold counterpart. But the fat was already there before you started cooking.

As Dutch consumer program Radar explains, toasting doesn't increase the calorie count or significantly change the sandwich's nutritional value.

Two slices of bread with two slices of cheese contain essentially the same calories whether you eat them hot or cold, provided you don't add anything else.

So why can grilled cheese contain more calories?

The difference usually comes down to preparation.

Many people spread butter on the outside of their grilled cheese to get that delicious, crispy crust. They may also use extra cheese, choose a fattier variety, or serve the sandwich with mayonnaise or another dipping sauce.

Those additions can make a noticeable difference.

For example, the Voedingscentrum calculates that a sandwich made with two slices of white bread, a reduced-fat spread, two slices of full-fat cheese, and one slice of ham contains approximately 459 calories and 13.6 grams of saturated fat.

Switching to whole wheat bread, one slice of reduced-fat cheese, a slice of ham, and a modest amount of reduced-fat spread brings its example down to 310 calories and 5 grams of saturated fat.

The ingredients, and not the melting, explain the difference.

The important difference is in the crust

There is one change that happens when bread is toasted at high temperatures.

According to the European Food Safety Authority (EFSA), starchy foods such as bread can produce a chemical called acrylamide when heated to temperatures above approximately 248°F (120°C).

Acrylamide forms during the browning process that gives toast its familiar flavor and color. Generally, the darker the bread becomes, the more acrylamide it can contain.

Animal studies have linked high acrylamide exposure to cancer. However, research involving humans has produced limited and inconsistent evidence.

In fact, Cancer Research UK says eating burnt toast is unlikely to increase cancer risk. Your overall diet matters much more than an occasional darkened sandwich.

Still, food safety authorities recommend reducing unnecessary exposure where practical.

The simple color rule food agencies recommend

The UK's Food Standards Agency recommends cooking starchy foods, including toast, until they're golden yellow or lighter, rather than dark brown.

The Dutch Voedingscentrum gives similar advice: avoid excessively dark toast.

That doesn't mean you need to throw away a sandwich because one corner turned slightly brown. It's simply a useful habit when cooking.

Four ways to make a lighter grilled cheese

If you enjoy grilled cheese regularly, a few small changes can make it a better everyday lunch:

1. Choose whole wheat bread for more fiber.
2. Skip the butter on the outside when using a nonstick pan or sandwich maker.
3. Use one slice of cheese instead of piling on several, preferably reduced-fat if you're watching saturated fat.
4. Toast until lightly golden, rather than letting the bread become dark brown or black.

You don't have to give up your favorite warm sandwich. With the same ingredients, grilled cheese and a cold cheese sandwich are nutritionally very similar.

Just remember that what goes into the sandwich matters more than whether the cheese is melted. And when it comes to the crust, lighter is generally better.