Kerstin is not going to Mexico with her church. They are going on their own.
And she is NOT a "nutritionist," despite misleading comments to the contrary on her Instagram. She's a health coach from a rather questionable (and expensive) online school, the Institute for Integrative Nutrition.
In fact, if you look up her school, it has some bad reviews online, particularly on Quackwatch, that basically says it's not an accredited school and that their enrollees don't even learn the basics of health or nutrition, but rather are encouraged to "coach" others using their own personal experience, which is obviously not necessarily grounded in science or best practices.
Kerstin often advocates intermittent fasting, which is not a healthy method of eating for certain people, particularly those with eating disorders, diabetes, heart disease, those who are pregnant, trying to get pregnant, or breast-feeding, AND it has questionable efficacy for weight loss. Just because it (seems) to work for her doesn't mean it's good for everyone. She admits that she fasts for 21 hours (or more) a day and only consumes broccoli, beets, hard boiled eggs, fish and an occasional steak. That sort of extreme eating is not sustainable for most of us.
She has been asked by QVC not to share food, health or nutrition advice because the Q is (wisely) afraid of a lawsuit.She admitted that on one of her QVC livestream episodes, so this is not a secret.
I just think it's important for folks to know she is in no way, shape, or form a nutritionist.
As well-meaning and sweet as you may find her to be, she's is unqualified to give medical advice, has no actual credentials and could give you some potentially harmful counsel.