Removing the skin and visible fat from chicken and turkey can lower the fat content by about 50%! Since the skin of chicken and turkey is the major contributor of saturated fat and cholesterol, removing the skin is a good technique to reduce the fat content of chicken and turkey for people who are trying to eat lean.
The breast is the leanest portion of poultry. Removing the skin from a six-ounce serving of boneless chicken breast, before cooking it, reduces the fat content, on average, from thirteen to seven grams.
If you're making a comparison to beef, you'll find that skinned baked chicken breast (the lowest-fat version possible) is fairly similar to the lowest-fat version of beef. Six ounces of skinned baked chicken breast will give you about seven grams of fat, while six ounces of eye of round steak (the lowest-fat cut of beef), trimmed of all visible fat, will give you about eight grams. But you won't do this well for trimmed top round (about 11 grams for 6 ounces) or trimmed bottom round (about 15 grams).
I have found that cooking poultry with the skin on and removing it after cooking makes little difference in the final fat content of the meat. But it can make a big difference in the moisture and taste. Cooking with the skin on keeps the meat insulated and allows it to retain more of its natural moisture and flavors. This is particularly important when cooking the breast portion of poultry, which can easily become dry and tough. When you peel off the skin after cooking, the meat may look much fattier but what you are seeing is not a large increase in fat, but a large increase in moisture.