“Everyone's weight fluctuates throughout the day, and especially from morning to night,” says dietitian Anne Danahy, MS, RDN. “The average change is 2 to 5 pounds, and it's due to fluid shifts throughout the day.” If you see fluctuations of less than 5 pounds, you needn't worry.
Is it possible to lose 5 pounds or more overnight? Yes, it is and it can be done safely by naturally reducing the amount of water your body retains but make no mistake that the weight loss will be mostly temporary.
The main thing that is changing overnight is the amount of water in your system. It's amazing how much water weighs! A gallon of water weighs 8 pounds, and a pint of water (16 ounces) weighs 1 pound (in metric, 1 liter of water weighs 1 kilogram).
Some causes of unintentional weight loss include: mental health conditions, such as depression, anxiety, eating disorders and obsessive compulsive disorder (OCD) problems with digestion, such as coeliac disease or irritable bowel syndrome (IBS)
Unexplained weight loss can occur in anyone. However, it is most common (and most serious) in people who are over the age of 65. Even unexplained weight loss of less than 5 percent of body weight or 10 pounds may be the sign of a serious condition in older people.
Rapid weight loss diet is a type of diet in which you lose more than 2 pounds (1 kilogram, kg) a week over several weeks.
The Bottom Line
You don't have to stress too much about the occasional overnight weight loss. It's normal for people who've lost water or glycogen to experience it—it's not a sign that you're losing fat rapidly.
How much weight loss is a concern. Your body weight can regularly fluctuate. But the persistent, unintentional loss of more than 5 per cent of your weight over 6 to 12 months is usually a cause for concern. Losing this much weight can be a sign of malnutrition.
Most significantly, your body is dehydrated because you haven't been consuming any liquids for several hours. So in the morning, you're carrying about 3-5 pounds less water weight than you are in the afternoon. So this really is the primary reason you weigh less in the morning.
On average, you sweat about 25ml per hour of sleep under temperate conditions (around 85 degrees Fahrenheit). ² If you sleep for an average of eight hours, that's around 200ml of sweat per night. This would equate to a drop in weight of approximately 200g overnight.
Health experts say that water loss from breathing and sweating alone can account for up to 83% of weight loss during sleep. The amount of water that individuals lose during the night will vary because not everyone has the same metabolic rate.
If you want to lose a small amount of weight quickly, you should do so effectively and safely, no matter your reason for wanting to shed pounds. However, you can safely shed weight from retained water and waste, and lose 5 lbs. (2.3 kg) or more within one day.
You might be retaining water. When you put your feet up at night, the water is able to travel back to your heart and get converted to urine which you will urinate upon waking up. You can lose a couple of kgs with that. Also, if you sweat at night, you can lose some weight there too.
You should step on the scale first thing in the morning. That's when you'll get your most accurate weight because your body has had the overnight hours to digest and process whatever you ate and drank the day before. And you should try to turn that step into a regular part of your routine.
The “whoosh effect” is a term for the noticeable weight loss that some people report while following low carb diets such as a keto diet. Some people believe that the whoosh effect happens when fat cells lose fat and fill with water. Researchers have not scientifically proven the whoosh effect, however.
Stress and weight loss
What's more, the stress hormones that our bodies release can speed up our metabolism, causing us to burn calories faster. In more extreme cases, prolonged stress may lead to depression, which can also cause weight loss.
Chronic infection such as AIDS. Chronic illness, such as COPD or Parkinson disease. Drugs, including chemotherapy drugs, and thyroid medicines. Drug abuse such as amphetamines and cocaine.
If you're losing weight without trying and you're concerned about it, consult your health care provider. As a rule of thumb, losing more than 5% of your weight over 6 to 12 months may indicate a problem.
While everyone loses weight differently, dropping as little as 3 to 5 pounds can show up on your face first, Eboli says. That's because when you exercise your whole body (and eat healthy), you burn fat all over.
Commonly performed tests include: Complete blood count (CBC): A complete blood count can reveal evidence of infections, anemia (which can be caused by many conditions that result in unintended weight loss), and more. Thyroid panel. Liver function tests.