I know someone who did the Whole 30 and lost a significant amount of weight. They also reported having more energy and better sleep.
A common success story with the Whole 30 is improved digestion. Many people notice fewer stomach issues and a more regular bowel movement. Another aspect is better control over sugar cravings and a more balanced diet overall.
I've heard that some people have seen positive changes in their skin after doing the Whole 30. They had clearer complexions and fewer breakouts. Also, mental clarity and reduced mood swings are often mentioned as benefits.