Which of the following statements about hunger and satiety are true?
I) Proteins contribute more to the feeling of satiety than carbohydrates.
II) Hormones contribute to both hunger and satiety signaling.
III) The frontal cortex is the brain region responsible for integrating hunger and satiety signals.

• A. I & II.
• B. II & III.
• C. I & III.
• D. I, II, & III.

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the key terms in the problem. 'Hunger' refers to the physiological need for food, while 'satiety' refers to the feeling of fullness that signals the cessation of eating. Proteins, carbohydrates, hormones, and brain regions are all involved in these processes.
2. Step 2: Analyze statement I: 'Proteins contribute more to the feeling of satiety than carbohydrates.' Proteins are known to have a higher satiety effect compared to carbohydrates because they take longer to digest and influence satiety hormones like peptide YY (PYY) and glucagon-like peptide-1 (GLP-1). This statement is true.
3. Step 3: Analyze statement II: 'Hormones contribute to both hunger and satiety signaling.' Hormones such as ghrelin (stimulates hunger) and leptin (promotes satiety) play critical roles in regulating hunger and satiety. This statement is true.
4. Step 4: Analyze statement III: 'The frontal cortex is the brain region responsible for integrating hunger and satiety signals.' The hypothalamus, not the frontal cortex, is the primary brain region responsible for integrating hunger and satiety signals. The frontal cortex is more involved in decision-making and self-control. This statement is false.
5. Step 5: Based on the analysis, determine which combination of statements is correct. Since statements I and II are true, and statement III is false, the correct answer is 'I & II.'