You may be eating better, but are you eating less? According to you’re not controlling portions, you could be sabotaging your weight-loss efforts.

“Problem is, a serving size and portion sizes are not always the same thing,” explains Deborah Beauvais, RD, a spokeswoman for the Academy of Nutrition and Dietetics.

But because no one wants to use measuring cups and scales for every little thing. The real trick to portion control is learning to eyeball portion sizes of common foods, like:

Baked Potato: A Woman’s Fist

You can certainly include a baked potato as part of a balanced diet. If you’re counting calories for weight loss, though, keep your potato small — about the size of a woman’s fist. “When possible, prepare potatoes with the skin intact,” Begun suggests. “Most of the fiber and many important nutrients reside in the skin.” Also, try herbs or spices rather than butter or sour cream as a topper.