Isagenix also stocks a multi-vitamin for children, which was advertised as having 16 essential vitamins to "promote healthy development of cartilage, bones and teeth, and support healthy metabolism and immunity".
Children from the age of 12 can then begin to take a daily cleanse product, as well as fish oil, vitamin C and protein concentrate.
"Many Isagenix products are appropriate for young kids and adolescents so they can start developing healthy habits at a young age and grow into strong, healthy, lean adults with a better quality of life," the company said on its website.
"It's never too late to help your kids develop nutritional habits that can last a lifetime," it reads.
Auckland University's Professor Peter Shepherd, who is the head of obesity and diabetes research at the Maurice Wilkins Centre, said he had never seen dietary supplements marketed so aggressively towards children.
"The products in questions are relatively standard dietary supplements and it's not advisable to have children using those products without medical supervision.
"It is in a key growth phase for children and they really need to have a controlled and balanced diet, and to have a good appreciation of food going on for the rest of their lives."
Prof Shepherd said there was no evidence to suggest that this type of diet had any long-term impact on the incidence or rates of childhood obesity.
"The reality is that the body is used to receiving and digesting food in a certain way and our hormones respond to those forms of ingestion much more naturally, and I think these types of artificial ways of administering food in an ongoing basis are not advisable unless there is a real medical need for it."
Prof Shepherd said he was surprised by the aggressive marketing towards children.
"I certainly don't think that's something we should be selling or doing in New Zealand."
Anna Bordignon is the founder of Munch Cooking, a website that makes and markets products and offers ideas and recipes to feed the family, as well as encouraging parents to feed their children the right kind of foods.
Ms Bordignon said it was completely inappropriate to market these types of products for children.
"It's all about moderate healthy food ... I don't think it's appropriate to market to children."
A mother-of-three, Ms Bordignon said there was no way she would ever encourage a parent to give these products to children.
"There are also psychological issues associated with that. What are you telling your children if you're telling them to diet at age four?"
Isagenix could not be immediately reached for comment.
