Katherine Zeratsky, a specialty editor for the Mayo Clinic nutrition and healthy eating guide, offers this on caffiene and its role in weight loss:
Caffeine may slightly boost weight loss or prevent weight gain, but there’s no sound evidence that increased caffeine consumption results in significant or permanent weight loss.
Caffeine is found in many beverages, including coffee, tea, energy drinks and colas; in products containing cocoa or chocolate; and in a variety of medications and dietary supplements, including supplements aimed at weight loss.
Some studies looking at caffeine and weight were poor quality or done on animals, making the results questionable or hard to generalize to humans. In addition, some studies found that even decaffeinated coffee may contribute to modest weight loss, suggesting that substances or factors besides caffeine may play a role in weight loss.
The bottom line: Be cautious about using caffeine products to help with weight loss. When used in moderation, caffeine is generally safe. But too much caffeine might cause nervousness, insomnia, nausea, increased blood pressure and other problems. Also, some caffeinated beverages, such as specialty coffees, are high in calories and fat. So instead of losing weight, you might actually gain weight if you drink too many of these.
This line stands out the most to me here: “When used in moderation, caffeine is generally safe. ”
If anyone says that “something” is “generally safe” when used in “moderation,” to me, that’s a red flag. Better to avoid using it, in the first place, rather than having to worry about if you’re in moderation and/or safe.