Weight gain and fluctuations in weight can happen for a variety of reasons. Many people progressively gain weight as they age or make changes to their lifestyle. However, fast weight gain can be a sign of an underlying health condition, such as a problem with the thyroid, kidneys, or heart.
Although you cannot control all the factors that cause unintentional weight gain, you can make changes to your lifestyle that make it easier for you to manage your weight—like eating a balanced diet, getting regular exercise, finding healthy outlets for stress, and sleeping 7 to 9 hours a night.
You Might Be Eating Too Little
This phenomenon is called “starvation mode,” and while your body isn't actually starving, it will naturally hold onto whatever calories it receives in an effort to help you maintain your energy balance.
But if you're eating healthy and exercising per usual and the number on your scale keeps going up, then that doesn't add up. Gained 20 pounds in a month? Now that's cause for concern. This kind of totally unexplained weight gain can signal more serious health problems such as a hormone condition or a reaction to an Rx.
Hormonal weight gain affects different areas in men and women. Men tend to gain excess weight in the abdominal area. However, premenopausal women add pounds around the hips and thighs. After menopause, women usually gain weight in the abdomen and develop a "menopausal belly."
Rapid weight gain or swelling in particular areas of the body can be due to fluid retention and may be a sign of heart failure. According to the American Heart Association , a weight gain of more than 2–3 pounds (lb) over 24 hours or 5 lb in a week could be a sign of heart failure.
The simple answer is no. There is no research to support the concept that not eating enough (or severe calorie restriction) can cause you to gain weight. Time and time again research has shown us that when we eat fewer calories than what we burn, we lose weight.
Regular meals, sleep, and exercise may all help boost metabolism. Calories provide the energy the body needs, not only to move but also to breathe, digest food, circulate blood, grow cells, repair wounds, and even to think. The rate at which the body burns calories to produce this energy is called the metabolic rate.
Although the prevalence of obesity increases with age, weight gain is actually greatest across the younger years of adult life — late twenties and thirties — and diminishes gradually over time as adults get older, says Tucker.
For most overweight people, their body tries to prevent permanent weight loss. This means your body is actually working against you to lose weight. That's because how much you weigh is controlled by complex interactions between hormones and neurons in your hypothalamus.
Men often gain weight until about age 55, and then begin to lose weight later in life. This may be related to a drop in the male sex hormone testosterone. Women usually gain weight until age 65, and then begin to lose weight.
The most obvious signs of a damaged, slow metabolism are weight gain, weight loss plateaus, and difficulty losing weight — even on a low-calorie diet with exercise. Many other signs and symptoms of a slow metabolism mirror those of hypothyroidism.
There's no solid proof that vitamin B-12 shots, also called injections, help you lose weight. Vitamin B-12 is a water-soluble B complex vitamin. It's found naturally in many foods, such as meat, fish and dairy products. Vitamin B-12 is added to some foods and is available as a dietary supplement.
Regular exercise increases muscle mass and teaches the body to burn kilojoules at a faster rate, even when at rest. Drugs – like caffeine or nicotine, can increase the BMR. Dietary deficiencies – for example, a diet low in iodine reduces thyroid function and slows the metabolism.
Not eating enough calories. If your body doesn't have enough fuel to sustain your level of activity, you can actually stop losing weight. Overtraining. If you exercise too much, the body sometimes responds by decreasing the amount of calories you burn during the rest of your day.
Muscle Mass
A month or two after you start exercising, your body composition may begin to change. You will likely gain muscle mass and may begin to lose some fat mass. Muscle weighs more than fat, but it also burns more calories.
The diet doesn't have enough calories
Eating too little — say, 1,000 calories a day — can prevent you from losing weight, too. "When you don't eat enough, your body is starving and it's not going to lose any extra weight" because it needs those energy stores to keep you alive, Fakhoury said.
If you're not losing weight in a calorie deficit you may need to adjust your stress levels, diet, and sleep patterns. Other reasons for weight gain during a calorie deficit are hormonal changes, aging, and other health conditions.
A classic sign of Prader-Willi syndrome is a constant craving for food, resulting in rapid weight gain, starting around age 2 years. Constant hunger leads to eating often and consuming large portions. Unusual food-seeking behaviors, such as hoarding food, or eating frozen food or even garbage, may develop.
You aren't eating enough calories.
"The biggest thing people do that slows their metabolism down is eating too few calories," said Fiore. 1200 calories per day is roughly the amount you need to perform basic functions, she suggested, and when a person eats fewer than that, the metabolism slows down to conserve energy.