Food scientist Chris Noonan says companies that suggest swapping meals for bars, shakes or even cereal cut calories, but at a cost. Like Special K.
"What they're advocating is eating a bowl of cereal for breakfast, a bowl for lunch and then your ordinary meal," says Noonan.
In addition, Special K doesn't contain any appreciable amount of fiber or protein, the ingredients that will help you stay full for a longer period of time.
Slim-Fast does offer more protein and fiber, however: "This is a short-term type of solution for a long-term problem," says Noonan.
Dietitian Ashley Koff says it's also hard for dieters to sustain for very long. She says many start out eating the prescribed plan, but as the days pass, they begin to add to the bars and shakes and cereal, which means more and more calories in their day. She suggests to her clients to check the nutrition facts to find out exactly what they are eating.
"If I'm asking my client to eat something like that, two times in a day, it had better be nutrient-dense," says Koff.
Then there's Cheerios' claim to lower cholesterol. In a six-week study participants had a 4 percent cholesterol reduction.
"It's a very modest reduction of cholesterol and certainly much better ways of getting a more impactful reduction in cholesterol, with higher fiber foods," says Noonan.
"Let's evaluate your whole diet, let's increase cruciferous vegetables, lets reduce added sugars, let's change our animal fats to some of our omega 3 fatty acids, and let's look at a 10-, 15-, 20-, 30-percent difference in our cholesterol reduction," says Koff.
Another claim: Activia yogurt with probiotics. "Eating Activia every day has been clinically proven to help digestive health in as little as two weeks," says a commercial.
Since lactose intolerance is a common cause of stomach distress, yogurt might not be the answer. And Koff says there's another issue.
"When we're dealing with digestive problems, we're talking six to eight weeks before you even see a basic difference," says Koff. "If you're looking for a product to actually address a digestive problem, that's where we go to the doctor or the dietitian and we work with a product that is clinically proven to do so."
"What they're trying to do with these messages is to increase usage, to sell more product and I think that's inappropriate," says Koff.
The experts say that, by and large, they feel that the food manufacturers have our best interests at heart. But they suggest rather than one food being the focus as the primary part of the diet, it should simply be part of a healthy one.