Final answer:
A food and symptom journal is the best tool for monitoring the effects of intermittent fasting as it allows for tracking food intake and bodily responses, providing a personalized and detailed record beyond just weight or blood pressure changes.
Step-by-step explanation:
Among the options provided for monitoring the effects of intermittent fasting and requiring individual adjustments, c. Food and symptom journal is the tool that can be most effectively used. Unlike merely tracking blood pressure or heart rate, a food and symptom journal allows for comprehensive monitoring of not just food intake but also the body's responses to the changes imposed by intermittent fasting.
It becomes a personalized record that reflects how one's body is adapting, including variables such as energy levels, mood changes, and physical symptoms. Although weight scale monitoring could provide some insights into overall weight changes, a food and symptom journal offers a nuanced view that encompasses various biological and physiological responses beyond weight, including potential improvements in metabolic markers or indications of stress or discomfort that may require adjustment of the fasting protocol.