If you complain that the food in the restaurant is not enough, you can consider the following steps to handle the complaint:

1. Communicate with the waiter: First, you can directly communicate with the waiter to express your dissatisfaction and problems. It's a misunderstanding or they can help you solve the problem.

2. Ask the manager to intervene: If the problem is not solved, you can ask to talk to the manager or person in charge of the restaurant. Explain your problem and describe in detail the situation you encountered during the meal.

3. Keep evidence: If possible, keep relevant evidence, such as food photos and order receipts, for future use.

4. Write a complaint letter or email: If the restaurant is not doing well in handling problems, you can consider writing a complaint letter or email in writing. Describe the problem clearly in the letter and provide relevant details and evidence. Explain how you want them to solve this problem, such as offering a refund and re-preparing food.

5. Use social media: In some cases, posting complaints through social media platforms (such as the official Facebook and Twitter of restaurants) will attract more attention. Make sure your expression is civilized, so as not to cause unnecessary controversy.