That's almost certainly psychosomatic. The sugars in the two are basically identical, and the creamer presumably has some fat in it, which would actually make it have a lower glycemic index (meaning the crash would be slower with the creamer).
This is mostly what the article calls the "halo effect". People assume that "natural" things are lower calorie or healthier, which is sometimes the case, but fructose is fructose. It doesn't really matter if it's from corn or honey. Honey arguably has another couple marginal benefits, but it's absolutely not useful in losing weight. It's something like 90% sugar by weight.
What I'd actually suspect is something closer to: all diets work. Almost every fad diet works, even when they're completely counter to nutritional science because the simple act of paying attention to what you eat has positive effects.
