A dog's appetite will increase significantly from about one month to seven months old. This is the so-called "embarrassing period" or "rapid growth period."

At this stage, the dog's body is developing rapidly, so the food intake may increase a lot.

However, if the dog always seems to be hungry, it may be due to the following reasons: 1. **Insufficient feeding**: The dog may be hungry due to insufficient feeding.

You should adjust the feeding amount appropriately according to the dog's weight, age, activity level, etc.

You can refer to the recommended feeding amounts on the dog food packaging, or consult a veterinarian or professional pet nutritionist.

2. **Low-quality feeding**: If your dog eats low-quality or nutritionally deficient dog food, he may feel hungry because he does not get enough energy.

You should choose high-quality, nutritionally balanced dog food.

3. **Excessive dog activity**: If your dog regularly engages in a lot of activities, it may increase its energy needs.

You should appropriately increase the amount of exercise your dog gets and make sure it gets enough rest time.

4. **Nutritional needs during the development period**: During the period of rapid growth, dogs have a greater demand for nutrients such as protein, fat, and carbohydrates. If they are not fed properly, they may suffer from malnutrition.

If your dog consistently doesn't eat enough, you should consider adjusting the amount and quality of the food you feed, and pay close attention to your dog's weight and physical condition.

If your dog is underweight or has other health problems, you should consult your veterinarian promptly for examination and treatment.