The answer is A: Eating only cold, green foods for one month.
Explanation for each option:
A. Eating only cold, green foods for one month - This is considered a fad diet because it involves an extreme and unbalanced approach to eating that is not sustainable or nutritionally adequate in the long term. Fad diets often promise quick results but lack scientific backing and can lead to nutritional deficiencies.
B. Joining Weight Watchers and a gym - This is not a fad diet. Weight Watchers is a well-established program that promotes balanced eating and lifestyle changes. Joining a gym complements this by encouraging regular physical activity, both of which are sustainable and healthy practices.
C. Eating mostly a plant-rich diet - This is not a fad diet. A plant-rich diet is generally considered healthy and sustainable, as it includes a variety of fruits, vegetables, whole grains, and legumes, providing essential nutrients and promoting overall well-being.
D. Adding time and new activities to a current workout plan - This is not a fad diet. It refers to enhancing physical activity, which is a positive and sustainable approach to improving fitness and health.
E. Limiting sweets to once per month - This is not a fad diet. Moderating the intake of sweets is a reasonable and healthy dietary practice that can help manage sugar consumption and promote better health.