It is not uncommon for body weight to fluctuate throughout the day. This is often the result of changes in fluid balance, which means that your body retains different amounts of water at various times of the day. For instance, when you wake up in the morning and you haven’t had anything to drink for several hours, you often weigh less than you do in the afternoon. There are also other factors that can affect fluid balance and, in turn, weight. Listed below are some of them. 

Sleep Deprivation

If you are not sleeping well, it can make you hungrier. A number of studies suggest that people who are sleep deprived are more likely to put on weight.

A recent research found that men and women who slept for less than five hours a night were more likely to experience weight gain than those who slept for seven hours.

According to the doctors, if you are awake for longer in a day it's more likely you'll eat maybe four or five meals and snacks rather than just the usual three if you have a full night's sleep. If you are sleep deprived, you have low energy so crave food to top up your energy levels.

Eating Diet Conscious Food

You may be focused on your weight and pick the low-fat options but sometimes these are high in sugar so may contain more calories than you think. Even if you are having big chunk of diet food, you may actually still be having too many calories.

According to leading nutritionists, diet food comes in small portions so people often have to have something else to fill them up, which actually backfires and defeats the weight-reduction goal.

Mindless Eating

Sometimes we eat without realizing why we are doing so. For instance, you are watching a movie with one hand constantly dipping into a bag of popcorn. Another example is eating lunch while you are working at your computer or checking emails. You don’t actually focus on what you are eating and how much you’ve eaten. That’s where you end up gaining those extra pounds around your belly.

Stress and Anxiety

We sometimes vouch for food in times of stress when we are really not that hungry but know it'll make us feel better. Stress eating is a form of emotional eating. You reach for food when you are anxious.

A medical study highlighted a gene that produces a protein at times of stress that increases our appetite and triggers a need for food.

There's also some reports suggesting that the hormone produced by your body in times of stress, cortisol, is linked to carrying extra weight around your tummy.

Moreover, when you get stressed it produces adrenaline which makes digestive system less active transferring it to your brain and muscles. You are not usually burning that stress off in an active way so the extra energy is stored as fat.

Endless Eating

You may not actually realize that you are taking in too many calories. Having a biscuit here and there adds up over the course of a week. Choosing crisp bread for lunch and then covering it with a layer of butter makes it a high-calorie choice rather than a diet option.

Eating out makes matters worse. Don't have a starter, main and a dessert just because everyone else is.

Certain Medications

Some medicines can make you gain weight. Some that often cause weight gain as a side effect include corticosteroids and anti-psychotic drugs. Some drugs can cause fluid retention which shows on the scales as weight gain.

Your thyroid levels may be behind your weight gain.

In the end, if you have concerns about losing weight, talk to your doctor. He’ll refer you to a dietician or nutritionist who’ll cater to your weight-losing needs.