I just read an advertisement for a weight-loss product in a newspaper from the chemist’s which was accompanied by three testimonials… all of which said, essentially, “I weighed [higher number], then I started taking [product] and exercising regularly and only [time] later, I only weighed [lower number]!”.
Gee. I wonder how much of the weight loss was the product and how much was the exercise. (They did specifically mention exercise in all three testimonials. One even put it this way: “I started taking [product] and a bit later also started to exercise regularly. Now I weigh [smaller number].”)
Kind of like, I don’t know, “My crops were starting to wither, so I prayed to God to save my wheat and I also started watering the plants. Only a short time later, my plants recovered and I was able to get a good harvest after all!”. Maybe the prayer helped, maybe it didn’t, but since you did two things, it’s hard to prove how much of the effect came from each “ingredient”.