Eggs!

Are eggs fattening? And is it true that they're bad for your heart? Mark, London, England

Here's the skinny on eggs: A single large egg has 75 calories, 63% of which comes from the 5 grams of fat that each contains. So, does that mean they're "fattening?" That depends on how many you eat over a given period of time.

The calories alone won't cause you exceed your daily limit, which for most adults falls somewhere between 1600 and 2800 calories, depending on your age, sex, body weight, and level of physical activity. Even a three-egg omelet isn't a huge caloric hit, relatively speaking, even though it's likely to be cooked in butter (more fat). However...

The percentage of fat in eggs is above desirable levels. Current dietary guidelines suggest that you should limit fat calories to about 30% of your total daily intake. That doesn't mean that you should never eat foods with higher percentages of fat, but obviously, the more high-fat foods you eat, the more difficult it will be to hit that 30% target. Still, if you ate just an egg or two per day, the high percentage of fat could be balanced by a generally low-fat diet. However...

Judging by your followup question, you've heard that eating eggs can contribute to heart disease. The facts are these: A single egg contain about 215 milligrams of cholesterol, which is two-thirds of the recommended daily allowance for healthy adults (300mg). High levels of blood cholesterol have been linked to heart disease. And although eating cholesterol (dietary cholesterol) doesn't necessarily lead directly to higher cholesterol production (blood cholesterol), foods rich in cholesterol often contain more fat and, specifically, saturated fat, which have been tagged as culprits in raising cholesterol. So...

The consensus seems to be that 3 or 4 eggs per week is a reasonable amount, with the yolks being the operative factor. If you eat just the egg whites, you can have many more and still stay within sensible dietary limits.
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