Moving more and eating less leads to weight loss, as long as you keep your calorie intake at a negative balance. A 1,200-calorie-per-day diet creates a caloric deficit for most people, but how much that deficit equals depends on the person. Everybody burns a different number of calories daily, depending on size, gender, age, body composition, genetics and physical activity. It takes a deficit of 3,500 calories to lose one pound -- the greater deficit you create, the more pounds you lose. For some people, 1,200 calories per day will lead to a large deficit that results in several pounds lost in a week. For other people, a 1,200-calorie diet creates a less dramatic deficit and may not yield significant weight loss for several months.
Weekly Weight Loss on a 1,200-Calorie Diet
The Dietary Guidelines for Americans estimate that the average woman burns from 1,600 to 2,400 calories per day and the average man needs between 2,000 and 3,000 calories daily. Larger and more active people tend to burn more calories per day; older, smaller and sedentary folks burn fewer.
If you're in the upper range of calorie burning, a 1,200-calorie-per-day diet can yield a weight loss of 2 or more pounds per week. For example, the average very active 35-year-old woman burns about 2,200 calories per day. If she trims her calorie intake to 1,200 calories, she'll create a deficit of 1,000 calories per day, which totals 7,000 calories -- or 2 pounds -- per week. However, a sedentary 55-year-old woman only burns about 1,600 calories per day. So, when she trims her intake to 1,200 calories, the deficit is a mere 400 calories, which yields a loss of only 0.8 pounds per week. Estimate your own daily caloric burn rate using an online calculator that takes into account your age, activity level, gender and size; then use trial and error to figure out roughly how many calories you burn daily.
1,200 Calories Is Too Little for Some
For some people, 1,200 calories is too few and may lead to weight loss, but also has serious consequences. A very active adult male, for example, needs between 2,800 and 3,000 calories per day to maintain his weight. If he trims to 1,200 calories, he's eating less than half of the calories his body needs. This can lead to a loss of energy, stalled metabolism, poor nutrient intake, diminished muscle mass and irritability -- if he can even sustain such a low calorie intake without becoming uncontrollably hungry.
The Stress of 1,200 Calories
Restricting calories to 1,200 per day also increases your stress level because you must monitor every bite that goes into your mouth. Following a 1,200-calorie diet, even for just a week, requires exceptional will power and resistance to hunger sensations. A study published in a 2010 issue of Psychosomatic Medicine showed that this increased stress and caloric restriction causes the body to pump out more of the stress hormone cortisol. Stress and increased cortisol production can cause your body to hold onto weight or to gain weight in the long run. Even if you're successful losing some weight with a 1,200-calorie-per-day diet in a week, the chronic stress of maintaining it over time may lead to health consequences such as heart disease, high blood pressure, diabetes and impaired immunity -- not to mention the quality of life issues associated with feeling stressed and hungry all the time.
Sustaining 1,200 Calories per Day
A 1,200-calorie per day diet might include three 300-calories meals and two 150-calorie snacks or three 400-calorie meals. Skipping meals, especially when restricting overall calorie intake, isn't recommended as it can lead to extreme hunger at later meals which may cause you to exceed your calorie goals. The smaller portions are probably less food than you're accustomed to eating and you may feel hungry between meals.
Each of your meals should contain 2 to 3 ounces of lean protein, such as white fish, chicken, tofu or trimmed beef. Stick to 1/2 cup of whole grains, such as brown rice, quinoa or one slice of whole-wheat bread, at most meals. Fill in the rest of your plate with leafy greens, which contain few calories while helping to fill you up. If you opt for snacks, make them cut-up veggies, 1/2 ounce of nuts, a small piece of fresh fruit or low-fat yogurt. A 1,200-calorie diet means you can't afford excess calories from refined grains, sugar or other treats.
Failure to Lose Weight on 1,200 Calories
If you fail to lose weight on 1,200 calories after a week, you may be consuming too few calories for your body. The lack of weight loss is your body's response to the stress caused by deprivation. In addition, if you're estimating your portion sizes instead of weighing and measuring them, you may be unknowingly eating more than 1,200 calories. Researchers have found that people often underestimate their calorie intake by about 30 percent, reports nutrition professor and author Marion Nestle in a 2012 issue of The Atlantic. So if you think you're consuming 1,200 calories, you may be eating more like 1,560 calories. If you're someone who burns just 1,600 calories per day, you may not see a change in the scale.
If you are certain you're consuming only 1,200 calories a day and aren't losing weight, don't try to trim calories further. Registered dietitian Joanne Larsen notes on her website, AsktheDietian.com, that no one should eat fewer calories unless under strict medical supervision because it leads to nutritional deficiencies. Instead, increase the amount of physical activity you do daily so you burn more calories and increase the deficit to encourage weight loss.