Which of the following statements is not true?

Fad diets often lack scientific research to support their claims.
Fad diets can cause health problems, such as osteoporosis and dehydration.
The weight lost on a fad diet is usually temporary.
Fad diets require lifestyle changes that teach sensible eating habits that last a lifetime.

The statement "Fad diets require lifestyle changes that teach sensible eating habits that last a lifetime" is not true. Fad diets usually focus on quick and temporary weight loss, rather than promoting long-term, sustainable changes in eating habits.