Over 73% of doctors would recommend a low calorie energy supplement to their healthy patients who use energy supplements.The way this is worded they basically said nothing of value. The doctors say they would recommend a low calorie supplement to people who are already using one to begin with, so there is no way to determine if these doctors would recommend it to people using nothing at all. Perhaps they only recommend it because it is better than using high calorie supplements that also do nothing, if the patient is going to use energy supplements anyway might as well turn them onto something low calorie right?
In addition they don't mention the 27% (a still pretty significant number) who didn't recommend it even within the very limited confines of the statements phrasing. What were their reasons?
Unfortunately shady advertising techniques like this one are used precisely because they work on enough people enough of the time to make it profitable. Laws can be useful to limit what advertisers claim to a certain extent, but as with this example it is often easy to come up with ways to say things that, while not outright lies, are intentionally misleading, thus circumventing the laws. This is one of the reasons that education in skeptical thinking is so important.