To make a weight loss plan more healthful, the best approach would be:
a. Decrease doses of dietary supplements
While dietary supplements can play a role in nutrition, megadoses are often unnecessary and could potentially lead to adverse health effects. It's generally better to focus on obtaining nutrients from a well-balanced diet of whole foods while maintaining regular physical activity and adequate hydration. The other options (decrease water, increase food portions, decrease physical activity) would not contribute to a healthful weight loss plan.