We know what you're thinking. You think that you're making a healthy choice by ordering that Diet Coke with your #3 big bargain meal. Not even close. While ordering a Diet Coke instead of a regular Coke will save you a couple hundred calories, the difference will hardly be notice-able because it will be buried in the obscene amount of calories found in the sandwich and fries.
Your effort to make a calorie-conscious decision is definitely applauded, but you need to be aware that a much more drastic step must be taken to make your fast food meal a part of a healthy nutrition plan. Skip the bargain meals altogether. While you may be getting more food for the same price, the extra food doesn't come alone. It will also bring you unwanted fat, calories, and cholesterol. Instead of ordering the #3, just order a regular-sized sandwich with small fries. Or better yet, substitute the sandwich for a salad and trade in the fries for a baked potato. Your options will vary from restaurant to restaurant, but going in there with this frame of mind will have you more prepared to make a smart food choice.