Fruit juices: Even juice from freshly squeezed fruit is still just sugar. Unless you are in the post-workout phase, this enormous dose of sugar is not only unnecessary—it also prompts an insulin spike that can boost fat storage and potentially increase insulin resistance. Plus, most juices have preservatives and additional flavorings, further eroding any of the nutrients. Instead, eat whole fresh fruit with fiber included to blunt the insulin response, fill you up and provide maximum nutrients. Or if you must have fruit juice, consider squeezing your own so you know exactly what’s in it.