One of the main reasons that undereating can lead to weight gain is because consuming too few calories can cause your resting metabolic rate to slow down. This means you may burn fewer calories throughout the day.
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.
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.
Not eating won't directly lead to weight gain -- in fact, you may lose weight as you'll temporarily eat fewer calories than you burn. The problem is that fasting is unsustainable, so any weight-loss benefit will likely be short lived and your health will pay the price.
Too few calories can hamper your metabolism, sabotaging any goal to lose weight. Although some combinations of macronutrients or types of foods may affect weight loss synergistically, when it comes to dropping pounds, there's no denying that calories matter.
However, other studies show that while consuming 1,000 calories a day may result in significant weight loss, most people cannot sustain it and often experience significant weight regain . The reasons include regaining lost muscle mass and increased appetite. Also worth noting is that the human body can adapt.
Consuming at least 1,200 calories per day has often been touted as the minimum for basic bodily functions and to stay out of starvation mode, but the amount is actually too low. A healthy amount of calories for adult women ranges from 1,800 to 2,400 calories per day and for men it's 2,000 to 3,200 calories per day.
However, calorie intake should not fall below 1,200 a day in women or 1,500 a day in men, except under the supervision of a health professional. Eating too few calories can endanger your health by depriving you of needed nutrients.
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.
So, if you're eating 1,200 calories and not losing weight, it could be that your body is really struggling to function on so little fuel and your metabolism is not functioning well enough to respond to a deficit in the way you'd like.
It simply takes time. Another common reason why people report not losing weight despite reducing their calories is that they don't give it enough time. Our bodies will do their utmost to hold on to our fat reserves and you often have to be in a calorie deficit for a while before you will see any meaningful weight loss.
A new exercise regimen puts stress on your muscle fibers. This causes small micro tears, also known as micro trauma, and some inflammation. Those two conditions in your muscle fibers are the reason you may gain some weight.
Muscle is denser than fat.
While one pound of fat weighs the same as one pound of muscle, muscle occupies about 18 percent less space. In addition, muscle burns calories while fat stores them. So, if your weight isn't decreasing but your clothes are starting to fit more loosely, you may be building muscle.
According to the National Institutes of Health, the average adult needs 1,600 to 3,000 calories per day. Although the exact number of calories needed vary based on age and physical activity, 700 is very low. A 2-year-old who engages in minimal physical activities needs at least 1000 calories in a day.
Most people need significantly more than 1,200 calories a day. Therefore, individuals who cut their daily intake to 1,200 calories can expect to lose some weight. This can be beneficial for people who are overweight or obese.
Some people may choose to restrict their daily intake to 1,500 calories. While factors such as age, gender, and activity level can cause caloric needs to vary, a 1,500-calorie intake is typically less than the average person requires. As a result, this diet may help some people lose weight.
First things first: It's totally normal for your weight to fluctuate 1-2kg in a day. Ever so often, patients come to me, saying: “I've tried several strict diet programmes and yet things go wrong. After all the hard work and effort I put in with diet and exercise, my weight doesn't budge.
Crash dieting
Transitioning from a very low calorie and low carbohydrate diet to a low calorie and moderate carbohydrate diet often leads to a weight gain of 1-2 kgs in a matter of one day. This is mainly because of a sudden increase in the carbohydrate content which is stored along with water in the body.
The good news is that you can't just gain 3kg of fat in 3 days. There are plenty of ways that your weight can fluctuate that aren't to do with your fat mass. Here are a few of the most common causes of sudden weight gain.
Some people go on a very low-calorie diet for rapid weight loss, often consuming only 800 calories a day. This type of diet usually includes special foods such as shakes, bars, or soups to replace meals and for added vitamins. Very low-calorie diets can help a person achieve weight loss of up to 3 to 5 pounds per week.
To lose one pound of weight per week, you should consume approximately 1,500 calories per day. Active women who walk for over 3 miles per day need to consume at least 2,200 calories to maintain their weight. To lose one pound of weight per week, you should consume approximately 1,700 calories per day.
No matter what type of diet you follow, to lose weight you need to burn more calories than you take in each day. For most people with overweight, cutting about 500 calories a day is a good place to start. If you can eat 500 fewer calories every day, you should lose about a pound (450 g) a week.