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.
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.
If you're eating healthily and still not losing weight, it could be because you're eating too much. Too much of a good thing can still cause you to gain weight (or simply stay the same and not lose weight). This is why it's important to eat in a calorie deficit and know what your calorie deficit is.
“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.”
A 1,200-calorie diet is much too low for most people and can result in negative side effects like dizziness, extreme hunger, nausea, micronutrient deficiencies, fatigue, headaches, and gallstones ( 23 ). Furthermore, a 1,200-calorie diet can set you up for failure if long-term weight loss is your goal.
It is possible that some people might not lose any weight or will need to remain on a restricted calorie diet for a significant time before seeing results. Weight loss will vary between people. For some people, an alternative approach, such as getting more exercise or consuming less sugar, might be a better option.
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.
The amount of food we consume daily has a significant impact on bodily function. Most adults need a minimum of 2000 calories to sustain metabolism, muscle activity, and brain function.
A 1,200 calorie diet, according to most nutritionists or food experts, is a restrictive, unsustainable, likely unhealthy diet for any adult woman.
You've gained muscle.
And here's an often overlooked fact: Muscle tissue is more dense than fat tissue. So as you gain more muscle and lose fat, you change your overall body composition, which can result in a higher weight, but a smaller figure and better health.
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. Closely tracking your weight during this window can be confusing—your clothes may feel looser while the number on the scale stays the same or even goes up a few pounds.
You're eating too much during your eating window.
“If you end up consuming the same number of calories (or more) during your eating windows as before you started intermittent fasting, then you won't lose weight.”
There are many reasons you can gain weight that have nothing to do with food. Sometimes weight gain is easy to figure out. If you've changed your eating habits, added more dessert or processed foods, or have been spending more time on the couch than usual, you can typically blame those reasons if you gain a few pounds.
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.
It is commonly said that if you eat too few calories, your metabolism will slow down to a point where you no longer lose weight. Part of this is true: as you lose weight your energy expenditure does drop. However, consuming too few calories cannot and will not cause you to gain weight. This is simply impossible.
In order to lose at least a pound a week, try to do at least 30 minutes of physical activity on most days, and reduce your daily calorie intake by at least 500 calories. 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.
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.
Not eating enough can stunt weight loss
When you severely reduce calorie intake, the body holds onto fat and turns to muscle stores for energy, which can slow your metabolism.