The reason cardio is controversial for weight loss is because of the phenomenon called over compensation. Some people over eat after they engage in cardio either because they overestimate the calories they burned through exercise, or they fall victim to an increase in hunger.
The solution is thus two-fold.
- Do not try to eat back the calories you burned (avoid food rewards for exercising).
- Start with less than 30 minutes of cardio a day. You should avoid fully depleting your energy stores to avoid the ravenous hunger.