Not eating kicks our body into 'starvation mode' pushing our body to conserve food and store it as fat. Not eating increases stress on the body. Stress releases steroid hormones to counter this threat and one side effect of steroids is weight gain. Skipping meals increases craving for junk food and processed food.
Many factors can contribute to unintentional weight gain. Poor sleep, sedentary activities, and eating too many processed or sugary foods are just some of the habits that may increase your risk of weight gain.
Eating too few calories can be the start of a vicious cycle that causes diet distress. When you cut your calories so low that your metabolism slows and you stop losing weight, you probably will become frustrated that your efforts are not paying off. This can lead you to overeat and ultimately gain weight.
You can't lose weight on 1200 calories a day because you're no longer in a calorie deficit. Your body has adapted to what it's been doing and plateaued. If you start your diet with a 500 calorie deficit per day, your body adapts to this in various way so that over time your energy requirements are reduced.
Your metabolism slows down about 2%-8% every decade. That may be from decreased muscle mass. Eating too little. It sounds strange, but the truth is, if you skip meals or follow a very low-calorie diet, it can backfire by making you burn calories more slowly.
Eating less than your body needs causes levels of cortisol to rise. This stress hormone causes the body to hold on to every morsel of fuel that comes its way. The best place to store those morsels is in the abdomen.
You can't get rid of that pesky belly fat.
While it might seem to go against traditional weight-loss logic, it all boils down to metabolism and hormones: Undereating promotes muscle loss and rises in the levels of the belly-fattening stress hormone cortisol over time.
Once you are an adult, your stomach pretty much remains the same size -- unless you have surgery to intentionally make it smaller. Eating less won't shrink your stomach, says Moyad, but it can help to reset your "appetite thermostat" so you won't feel as hungry, and it may be easier to stick with your eating plan.
It simply goes back to its previous size once it digests your food. Your stomach is constantly expanding and shrinking to accommodate your food. You can't consistently change its physical size by eating differently or in really small amounts. For example, not eating won't cause your stomach to shrink over time.
Because it is a distensible organ, it normally expands to hold about one litre of food. The stomach of a newborn human baby will only be able to retain about 30 millilitres. The maximum stomach volume in adults is between 2 and 4 litres.
It has been proven that when a person eats less, the body has less food to convert into stools, which naturally causes constipation. It further affects the entire digestive system resulting in other abdomen issues.
After eight hours without eating, your body will begin to use stored fats for energy. Your body will continue to use stored fat to create energy throughout the remainder of your 24-hour fast. Fasts that last longer than 24 hours may lead to your body to start converting stored proteins into energy.
If you have a big meal, your stomach doesn't magically get bigger and stay that way—it shrinks back down to its previous size in about four hours or less as your food is pushed along to the small intestine, Staller says.
You're holding onto water weight.
It's as simple as that really, unless you're incredibly small and in active you should and will lose weight on 1000 calories unless of course you're chronically stressed or really suck at counting calories.
As a general rule, people need a minimum of 1,200 calories daily to stay healthy. People who have a strenuous fitness routine or perform many daily activities need more calories. If you have reduced your calorie intake below 1,200 calories a day, you could be hurting your body in addition to your weight-loss plans.
Over time, your body responds to calorie deprivation by reducing your resting metabolic rate (RMR) via adaptive thermogenesis (metabolic adaptation). This makes your body less effective at burning calories in an effort to preserve as much energy as possible ( 7 , 8 , 9 ).
Your slower metabolism will slow your weight loss, even if you eat the same number of calories that helped you lose weight. When the calories you burn equal the calories you eat, you reach a plateau. To lose more weight, you need to either increase your physical activity or decrease the calories you eat.
This is called a weight loss plateau. The initial weight loss is usually just water weight and not fat loss. The plateau is caused by loss of muscle that occurs during weight loss (if you are not working out). To counter this, you can either cut more calories or increase your physical activity.
For example, to lose 1 to 2 pounds a week — a rate that experts consider safe — your food consumption should provide 500 to 1,000 calories less than your total weight-maintenance calories. If you need 2,325 calories a day to maintain your current weight, reduce your daily calories to between 1,325 and 1,825.
“And then, of course, everybody's metabolism is slightly different. But the average weight loss that most people see on the 1200 calorie diet is about one to two pounds per week.”
The fact is very-low-calorie diets (~1,000 to 1,200 calories or less) are contributing to weight gain more than they are helping people to find lasting weight loss.
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.
You've Gained Muscle Mass
If you're exercising regularly and doing a mix of cardio and strength training, it's very likely your body composition (ratio of muscle to fat) is changing for the better. If you're gaining muscle while losing fat, the scale may not show any weight change.