Jennifer Lopez struggled to indulge in her carbohydrate cravings at the end of her 10-day diet challenge, because cutting out the key food group has shrunk her appetite.

The Wedding Planner star and her boyfriend, retired baseball ace Alex Rodriguez, decided to clean up their diets by avoiding all sugar and carbs for the trial, which proved to be tougher than the couple had initially thought.

J.Lo and A-Rod both documented their efforts on social media, where the singer/actress openly admitted she was finding it particularly hard just two days into the challenge.

"It turns out that when you don't have sugar and you don't have carbs, you're really, really hungry all the time!" she cringed in one clip, as she and her team of nutritionists tried to come up with new snack ideas for the pair to feast on.

Both Jennifer and Alex managed to complete their tough task without any cheating, and after finishing the feat on Wednesday (30Jan19), they decided to spend the next day eating carbs until their hearts' delight.

However, Jennifer claims she wasn't able to feast on her favourite foods like she used to, because her body had already adjusted to the lack of sugar and carbs.

"Right when it was over, it was funny, I was like, 'I'm gonna get up in the morning and have oatmeal,' 'cause I just needed some carbs...," she told U.S. breakfast show Today, "and then I only had like, three bites and I was like, 'I'm done with this.'"

"I don't know (why), you just don't have as much of a craving," Jennifer lamented. "Then during the day I said I was gonna cook, so I cooked and then I ate, (but) you just can't fit as much down."

While the superstar cooked up a series of traditional Puerto Rican dishes, including rice, beans, and fried plantains, her boyfriend chose a different route, and went all out with pizza, chicken wings, fries, cookies, and more.

"Alex went crazy!" she laughed.

Jennifer is now planning to go back onto the no sugar, no carb diet, because she believes it really made a difference to her body.

"I was dreaming about what I was gonna eat (once the challenge was over), but the truth is, you get to a point where you can't fit that much down after you remove that much of the carbs, because that's really what bloats you and gives you all of that inflammation...," she said. "I'm gonna do five days just eating normal, and then I'm gonna back and do it for another 10 days."

It's not clear if Alex will be joining her on the second round, but J.Lo has encouraged fans interested in taking on their 10 Day Challenge to push through the diet with her when she resumes the strict food plan.