It is best to take them about a half hour before main meals, no more than recommended.
Some of the ingredients in some of the diet supplements are time activated and work best with food, but need to be activated first, which is why the time frame. There are also some supplements that don't work unless you eat.
I can give you some supplements that will enhance your weight loss without taking things like Trim Spa, or even will enhance WITH Trim Spa, just depends on how much money you want to spend.
Sorry if I keep going on and on, but it has been awhile, lol.