While these substitutes—like aspartame, saccharin and Splenda—have not been proven to be dangerous, Dr. Oz says they also haven't been proven to promote weight loss.
"When you have a sugar substitute, your brain knows that you're not really taking calories in. It can't be tricked. At the end of the day, you're still going to get your calories," he says. "There's a lot of data behind this. Don't think that by taking a diet food that has a sugar replacement in it that you're actually going to be able to lose weight because of that. That's not how it works. Artificial sweeteners do not lead to weight loss, unless it's the only way to get you off the simple sugars that we have in our drinks all the time."
Dr. Oz encourages people to drink 100 percent fruit juice. Despite their high calories, these juices have valuable nutrients. "You're only going to be able to diet long-term if you aim at a hundred calories. Don't try to lose 500 a day," he says. "You can cut a hundred calories a day just by being smarter in what you eat."