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.
Calories and Your Health
But if your calorie intake dips too low, says Lummus, your body could go into starvation mode. "Your body will start to store fat because it thinks it is not going to get anything," says Lummus. "You will be at a point where your body is kind of at a standstill."
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.
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.
For most people, a calorie deficit of 500 calories per day is sufficient for weight loss and unlikely to significantly affect your hunger or energy levels (2).
1. It Can Lower Your Metabolism. Regularly eating fewer calories than your body needs can cause your metabolism to slow down. Several studies show that low-calorie diets can decrease the number of calories the body burns by as much as 23% ( 8 , 9 , 10 ).
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.
One of the main reasons why burning calories through exercise may still not result in weight loss is due to overexertion, or inflammation of your body. If you exercise too hard on a daily basis, there is an excess of inflammation in your body. All the added up inflammation makes you gain more weight than lose.
Following a 2,000-calorie diet may help some people lose weight. Its effectiveness for this purpose depends on your age, gender, height, weight, activity level, and weight loss goals. It's important to note that weight loss is much more complicated than simply reducing your calorie intake.
If you drastically slash calories and are eating a very low-calorie diet (Think: less than 1,000 calories for women and less than 1,200 calories for men), “starvation mode” can actually be starvation. Starvation from chronic undereating can be counterproductive to weight loss and dangerous to your health.
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.
Short-term fasts boost metabolism by up to 14%
It's well established that very long periods without food can cause a drop in metabolism ( 28 , 29 ). However, some older studies have shown that fasting for short periods can actually increase your metabolism, not slow it down ( 30 , 31 ).
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.
The Calorie Deficit
Even if you have more progress to make, I never recommend sitting in a calorie deficit for longer than 12 weeks before initiating a maintenance phase for an equal or greater amount of time.
As we've mentioned, eating less than 1000 calories a day will lead to a slowed metabolism, loss of muscle mass, malnutrition, the body to enter into starvation mode and all of this is not healthy for you.
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.
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.
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.
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.
Bare Number of Calories
The National Institute of Diabetes and Digestive and Kidney Diseases says that when eating real food, women may be able to meet their needs eating as few as 1,000 to 1,200 calories a day, and men can do the same on 1,200 to 1,600 calories a day.
Eat plenty of protein with each meal — 25 to 30 percent of your total daily calories — to boost your metabolism. Aim for at least 8 hours of high-quality sleep per night. Eat probiotic-rich foods (or take probiotic supplements). Meditate daily to keep stress to a minimum.