What is unexpected weight gain?

This means gaining weight even though you have not changed your eating habits or activity level. Weight gain can happen quickly over a few days or weeks, or more slowly over a longer period of time.

Small changes in your weight are normal. But gaining weight without a clear reason can sometimes be a sign of a health problem.

It is important to see your doctor or nurse if you are not trying to gain weight, and:

• Your weight goes up by 5 to 10 pounds (2.5 to 5 kg) in 1 to 2 weeks.

• You gain more than 5 percent of your body weight over a short period of time, like 6 months. An example is a person who weighs 150 pounds (68 kg) gaining about 8 pounds (4 kg) over 6 months.

What can cause unexpected weight gain?

There are many possible reasons why you might gain weight without trying. Examples include:

• Life changes, like puberty or pregnancy

• Aging – As you get older, it is common to gradually gain weight. Many people continue to gain weight until about age 65 years. In people who go through menopause, it is also common to gain weight, especially in the belly area after monthly periods stop.

• Lifestyle changes – It is common for a person to take in more calories than they need without realizing. Things like poor sleep, changing jobs or switching to a less active job, stress, or quitting smoking can all lead to weight gain.

• Some medicines, like steroids or medicines to treat diabetes, depression, and other mental health conditions

• Medical conditions – Some medical conditions can affect your weight. Examples include an underactive thyroid, polycystic ovary syndrome, and Cushing syndrome. Liver, kidney, or heart problems can also cause the body to collect extra fluid in its tissues. The extra fluid can cause weight gain.

Will I need tests?

Maybe. Your doctor will start by asking about your weight gain and doing an exam. They might also do blood tests.

How is unexpected weight gain treated?

The right treatment depends on what is causing the weight gain.

Treatment might include:

• Care for a medical condition

• Lifestyle changes – Your doctor or nurse might suggest you increase your activity level, get more sleep, or change your diet to eat fewer calories.

• Reviewing or changing your medicines – Do not stop or change your medicines without talking with your doctor or nurse.

Your doctor might recommend taking medicine to help lose weight, as well as making lifestyle changes. This depends on several things, including what caused your weight gain and if you have any medical conditions. It also depends on your weight. If you are interested in trying medicine, talk to your doctor or nurse. They can help you understand the benefits and risks.

What can I do on my own?

For most people who do not have signs or symptoms of a medical problem (like heart disease), weight gain is caused by taking in too many calories.

You can try keeping a food diary for a few weeks. This means you write down everything you eat and track your calories. Then, you can see if there are ways you can change your eating habits. For example, some healthy foods like nuts and avocados have more calories than you might think. Even a small amount of extra calories over a day or week can lead to unexpected weight gain over time. Also, track your activity levels to see how many calories you are using each day.

If you and your doctor think you gained weight because of your eating or lifestyle habits, you can make changes. To lose weight, you can reduce the calories in your diet, burn more calories through exercise, or both. It is often not easy to lose weight, but it can have a very positive effect on your health.

• Diet – There is no specific diet plan that works for everyone. Many "trendy" weight loss programs can be more harmful than helpful. Any diet that reduces how many calories you eat can help you lose weight, as long as you stick with it. Try to find an eating pattern that works for you.

  It can also help to work with a dietitian (food expert). They can help you make healthy diet changes while making sure you get the nutrients your body needs.

• Movement and exercise – Even gentle forms of exercise are good for your health. You can walk, dance, garden, or even just move your arms while sitting. For weight loss, the important thing is to increase how many calories you burn by moving more.

Combining a healthy diet with regular physical activity can help you get the best results.

When should I call the doctor?

Call for advice if you:

• Gain weight quickly, and have shortness of breath or swelling

• Feel more tired or weak than usual

• Have swelling in your feet, ankles, legs, hands, face, or belly

• Have constipation or dry skin

• Feel cold more often than usual

• Have changes to your periods

• Think a medicine is causing your weight gain