Terry Voltaggio stays fit with the help of an app on her smart phone called MyFitnessPal.
"All I have to do is find the food I've eaten, select the number of servings, and it goes right into my calorie count for the day," Voltaggio said.
MyFitnessPal was among the top-rated in Consumer Reports' survey of its subscribers.
"People who used MyFitnessPal said it made them very aware of how many calories they were eating and how much they were exercising," Consumer Reports' Nancy Metcalf said.
MyFitnessPal has useful features like a barcode scanner that automatically enters the amount of calories per serving. You can also track how many calories you burn exercising. And on its website, you can get encouragement from others using the program.
"We also rated commercial diets, which you generally have to pay to join, and in some cases, buy their prepackaged food," Metcalf said.
Nutrisystem was the lowest-rated commercial diet. More than a third of those surveyed who tried it didn't like the plan's food.
"Among commercial diet plans, Weight Watchers scored much higher -- higher than Jenny Craig. It works a bit differently. You don't have to buy their food, and you can eat whatever you want within their points limit," Metcalf said.
You can attend Weight Watchers meetings and track your diet online. However, Terry is happy with MyFitnessPal, which is free.
"I'll lose 10 pounds easy. It's a great tool for me," Voltaggio said.
There's another do-it-yourself diet that did well in Consumer Reports' survey. It's called the paleo diet, named after the paleolithic age in which prehistoric man survived by hunting and gathering. It instructs dieters to eat what cavemen ate - lean meats, seafood, fruits and vegetables. And you must avoid they things they didn't eat, including processed foods and dairy.