Lummus says that when your body goes into starvation mode, your metabolism slows to a crawl, burning calories as slowly as possible to conserve its energy stores. This is why people who cut their calories too much may reach a plateau and stop losing weight.
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. “The big picture is to consume enough calories with a balance of nutrients and engage in physical activity for good health management to achieve one's weight goals.
If you're not getting enough calories, chances are you're not getting enough vitamins and minerals either. Nutritional deficiencies may cause a long list of health complications including, but not limited to, anemia, infertility, bone loss, poor dental health and decreased thyroid function.
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.
If you're a man, woman weighing over 164 pounds or a female who regularly exercises and you aren't losing weight eating 1,200 to 1,500 calories daily, it may be time to see a doctor. Hormone imbalances – such as underactive thyroid – can decrease your body's metabolism and inhibit or prevent weight loss from occurring.
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.
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.
Very low-calorie diets (around 800 calories per day), cause rapid weight loss and increase the risk of gallstones, which may cause abdominal pain and require surgery.
Unintentional weight gain occurs when you put on weight without increasing your consumption of food or liquid and without decreasing your activity. This occurs when you're not trying to gain weight. It's often due to fluid retention, abnormal growths, constipation, or pregnancy.
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.
According to the 2020–2025 Dietary Guidelines for Americans, most adult females require between 1,600 and 2,000 calories, and adult males between 2,000 and 2,400 calories, per day. Consequently, most people will lose weight following a 1,500- to 1,800-calorie diet.
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.
Starvation calories are an intake of fewer than 600 calories per day, however; any caloric intake below the recommended minimum doesn't provide the body with the fuel it needs to function properly. A starvation diet doesn't promote weight loss because your metabolism slows down in response to low caloric intake.
Generally, the recommended daily calorie intake is 2,000 calories a day for women and 2,500 for men.
Undereating may cause weight gain for some people, but even if it doesn't, it's important not to eat so little that it adversely affects your health. From constipation to immune dysfunction, not eating enough can lead to a host of health issues.
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.
Without enough calories, you will quickly experience feelings of fatigue. Because your body doesn't have enough calories to burn and generate energy. You've been losing hair. This is another consequence of a lack of nutrients.
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.
You will not gain weight from eating too few calories.
There are many reasons why it can seem like under-eating can lead to weight gain. But, science has shown over and over again that this isn't physiologically possible.
Factors such as eating salty foods, high-carb diets, hormonal changes in your body, some medications, and lack of exercise can lead to water retention. Water retention can reflect a high weight on a scale even if you are on a calorie deficit.
In terms of how your body looks, “it usually takes 4 weeks for your friends to notice weight loss, and 6–8 weeks for you to notice,” says Ramsey Bergeron, a certified personal trainer. “Your friends who don't see you every day are much more likely to see a change than someone you're around all the time,” he adds.