The berries probably didn't *weigh* 8 ounces -- it is physically impossible for them to be transmuted into 3 pounds of fat! Any overnight weight fluctuation like that is water weight and can be completely disregarded. The weight gain is entirely coincidental to the berries and is most likely the result of something salty you ate that day as well. If you ever go on a major carb binge, you will notice that you gain some water weight, as 1g of carbs attracts 4g of water, but a couple strawberries aren't enough to account for 3 pounds. Day-to-day fluctuations like that are very normal and should be ignored.