There are many different kinds of harmful poisons that interfere with metabolic functions. One such compound is 2,4-Dinitrophenol or DNP. This has been used in industry as a dye and wood preservative. It was even once used as a dieting aid back in the 1930's due to it's ability to increase metabolic rate.
The drug works by binding to H+ ions and then transporting them across a membrane. It is fat soluble so it can cross membranes freely and it takes H+ ions along with it. This makes it a metabolic uncoupler.
Based on what you know about metabolism and H+ gradients, what effect would DNP have on cells? Why would this cause metabolism to speed up so it could be used as a diet drug?