When we fall sick for a long period of time, we become thin. Give reason.

Explanation

### Step-by-Step Solution:

1. **Understanding Weight Loss During Illness**: When a person is sick for an extended period, they often experience weight loss. This is a common observation and can be attributed to several physiological changes in the body.

2. **Metabolism Changes**: When the body is fighting an infection, the metabolism increases. The body requires more energy to combat the illness, which leads to the utilization of stored energy reserves, such as fats and carbohydrates. This increased metabolic rate can result in weight loss.

3. **Increased Body Temperature**: Illness often leads to an increase in body temperature, commonly known as fever. The body works harder to regulate this temperature, which further increases energy expenditure. This can contribute to weight loss as the body burns more calories.

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