"I'm very happy with the results so far!" the Cake Boss star shared on Instagram.

Buddy Valastro recently revealed on Instagram that he has slimmed down using a diet program called Optavia.

“I’m not being paid to say this and it should be noted that I think every body is different and you should do whatever suits you but this is what I’m doing and I’m very happy with the results so far!” the Cake Boss star wrote.

The program features a variety of plans you can choose from that deliver nutritious snacks and meals. The goal on each plan is to eat six times a day.

To get started, potential customers can fill out a questionnaire to find out what plan will work best for their lifestyle and then they can chat with a coach, learn healthy recipes, and educate themselves through dining guides and health books after signing up.

Credit: Buddy Valastro/Instagram

As Valastro can attest to, this type of weight-loss program can be successful for losing weight quickly. To get the scoop on the diet’s overall effectiveness, PEOPLE talked to registered dietitian nutritionist Marisa Moore—who says it is usually not sustainable.

“Without learning and incorporating the necessary behavior and lifestyle changes required for well balanced and healthy living, it can be difficult to maintain,” Moore says.

She also notes that the quality of the meals is much more important that the quantity. The plan, which starts at $400 for 30 days worth of food, offers things like packaged cookies, popcorn, crackers, brownies and bars, but Moore suggests loading your plate with veggies, fruit and lean protein.

“The number of meals you should have in a day will vary by person,” she says. “It will vary with what’s in the meals and daily activity level, for example. Routinely eating too few calories and skimping on protein or fiber can leave you feeling hungry and dissatisfied and more likely to reach for treats.”

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Moore says she does support the “small step approach and can appreciate their micro habits to health.”

“I would encourage anyone adopting a new program to do extensive research and work with a credentialed professional like a registered dietitian nutritionist,” she adds.