Unexplained Weight Gain

What is unexplained weight gain?

Unexplained weight gain means you’ve put on some pounds even though you haven’t deliberately increased your food intake or decreased your physical activity. In simple terms, it’s gaining weight when you’re not trying to. It can happen slowly over time, or you may experience rapid weight gain.

It’s normal to have weight changes throughout your life. Most of the time, it’s just a natural part of being human. But sometimes, unexplained weight loss or unexpected weight gain can mean you have an underlying health issue. If you’ve noticed dramatic weight changes recently, it’s important to let your healthcare provider know.

What is considered rapid weight gain?

Healthcare providers consider rapid weight gain to be a major increase in your body weight over a short period of time. If you gain 2 to 3 pounds a day, or 5 pounds a week, you should see your provider. It’s also important to see them if you gain 5% or more of your body weight in a month. This type of unexpected weight gain may be a sign of an underlying health condition.

What causes unexplained or sudden weight gain?

There are many reasons why you could gain weight unintentionally. Causes of unexplained weight gain range from getting older and hormonal changes to health conditions and medications.

Aging

Your metabolism slows down as you grow older. As you lose muscle and bone density, you gain body fat. It takes fewer calories to maintain fat than it does to maintain muscle. Unless you change the amount of calories you take in as you age, you’ll likely continue to gain weight.

Hormonal changes

You’re more likely to have unexpected weight gain during certain phases of your life, like:

• Puberty. When children enter puberty, they usually have growth spurts. During this time, they gain weight, grow taller and increase their muscle mass.
• Menstruation. It’s common to gain a few pounds during your period. This is often a result of changing hormone levels and water retention.
• Pregnancy. It’s normal and natural to gain weight during pregnancy. It’s also important. Ask your healthcare provider about recommended weight gain during pregnancy based on your body mass index (BMI).
• Menopause. Many people experience unexplained weight gain during menopause as estrogen levels begin to decline.

Lifestyle changes

It’s no surprise that an increase in food intake or decrease in physical activity can cause weight gain. But there are many other lifestyle factors that can impact your weight, including:

• Stress. When you’re under stress, your body releases cortisol. Cortisol is a hormone that increases sugar in your bloodstream and adds to fat storage in your belly. Cortisol can also make you crave higher-calorie foods.
• Lack of sleep. If you don’t get enough energy through sleep, your body will try to get that energy through food. Without plenty of sleep, your body produces higher levels of hunger hormones (ghrelin and leptin). Ghrelin increases your appetite, and leptin makes you feel less full.
• Quitting smoking. The decision to stop smoking is always the right one. But some people gain a few pounds after quitting. This is because nicotine speeds up your metabolism and makes you less hungry. So, when you kick the habit, you might head to the kitchen.
• Chronic dieting. Fad diets can actually cause weight gain. And with weight cycling, you’re repeatedly losing weight and gaining it back again. Diet plans like these also put you at a higher risk of developing long-term physical and mental health conditions.

Health conditions

Certain medical conditions can lead to unexplained weight gain. These conditions may include:

• Endocrine disorders. These include conditions like thyroid hormone deficiency, insulin resistance and polycystic ovary syndrome (PCOS).
• Edema (swelling). This happens when fluid builds up in your tissues. It most often affects your legs, ankles and feet. Edema has many causes. But it can be a symptom of lung, liver or kidney diseases.
• Depression. There’s a complex link between depression and weight gain. People with depression are more likely to develop obesity. And people with obesity are more likely to develop depression. This creates a cycle that can be difficult to break.

Medications

Unexplained or rapid weight gain is a possible side effect of many medications, including:

• Antidepressants
• Antipsychotic medications
• Birth control pills
• Blood pressure medications
• Corticosteroids

If you noticed unexpected weight gain after starting a new medication, let your healthcare provider know.

How do you treat unexplained weight gain?

Treatment depends on what caused the unexpected or sudden weight gain. What works for one person might not work for you. To figure out why you’re gaining weight, a healthcare provider will do a physical examination. They’ll also calculate your body mass index (BMI), and they may run lab tests to check your hormone levels.

Once your provider determines the underlying cause of the weight gain, they’ll work with you to design a personalized treatment plan. This may include:

• Medications (or changes to current medications)
• Lifestyle changes
• Mindfulness practices

How can I prevent unexpected weight gain?

You can’t always prevent unexplained or rapid weight gain. In many cases, it’s a symptom beyond your control. But if you think the weight gain is a result of your eating or lifestyle habits, here are a few things you can try:

• Reduce your intake of sugar
• Cut back on processed foods
• Eat portion sizes that are healthy for you
• Find a physical activity you enjoy and do it for 30 minutes every day
• Practice mindfulness with meditation or yoga

When should I see a healthcare provider about unexplained weight gain?

You should schedule an appointment with your healthcare provider if you have weight gain along with:

• Constipation
• Excessive sweating
• Feeling colder than usual
• Fever
• Hair loss
• Heart palpitations
• Shortness of breath
• Vision changes