Passage Summary: An advertisement claims that because a study showed successful dieters ate high protein and big breakfasts, anyone who follows their high-protein, big-breakfast diet is guaranteed to lose weight.

Conclusion: Following this specific diet will definitely result in weight loss for any individual.

Reasoning: A study found that the most successful dieters consumed more protein than carbohydrates and ate their largest meal early in the day, which are the core requirements of this diet.

Analysis: The argument makes a classic leap from correlation to causation. Just because successful dieters in a study happened to share certain eating habits doesn't mean those habits were the actual cause of their weight loss, nor does it guarantee the same results for everyone else. Furthermore, the advertisement assumes that what was true for the 'most successful' group in a study will apply to 'anyone' who tries the diet. Look for an answer that points out that the advertisement ignores other factors—like total caloric intake—that might actually be responsible for weight loss.