In the event of starvation, after consumption of glycogen and fats, the next nutrient that is to be consumed is

The correct option is proteins.

During prolonged fasting or starvation, the human body obtains energy by utilizing its stored nutrients in a highly regulated, sequential manner to ensure survival. Let us break down this process step-by-step:
1. Carbohydrate Depletion (Glycogen): The body first uses its immediate carbohydrate reserves. Glycogen stored in the liver and skeletal muscles is broken down into glucose to support energy demands, particularly for the brain. These stores are typically depleted within 12 to 24 hours.
2. Fat Mobilization (Lipids): Once glycogen is exhausted, the body shifts to consuming fat reserves. Adipose tissue releases fatty acids and glycerol, which are metabolized to generate energy and ketone bodies. This phase can last for weeks depending on the individual's body fat percentage.
3. Protein Breakdown: When both glycogen and fat stores are virtually depleted, the body has no other major energy reserves. It begins to break down structural and functional proteins (primarily from skeletal muscle) into amino acids. These amino acids are converted into glucose via gluconeogenesis in the liver to sustain vital organ functions.

Why other options are incorrect:
- Starch and cellulose are plant-based carbohydrates. Starch is not stored in the human body, and cellulose cannot be digested by humans due to the lack of the cellulase enzyme.
- Adenosine triphosphate (ATP) is the immediate energy currency of cells, not a stored nutrient resource consumed in sequential stages of starvation.