Is Your Low-Cal Diet Wrecking Your Health?

Dieting too aggressively by dramatically slashing calories can put your hormonal and overall health in jeopardy.

Ugh. As if losing weight wasn’t hard enough already, nature threw women a curveball: hormones. Even though it's human nature to want results as quickly as possible, dieting too aggressively by drastically cutting calories can put your health in jeopardy.

It’s dangerous to try to approach weight loss as an all-out sprint. When you’re trying to lose weight, your goal is to use more energy than you’re taking in. And the two easiest ways to do this are to exercise more and eat less.

The Dangers of Too-Low-Calorie Diets

But even though the formula is simple on paper, dieting in real life isn't always as easy as calories in vs. calories out. For women, being too aggressive with weight loss can throw your hormones out of whack, with dangerous consequences.

This happens so often with female athletes and fitness enthusiasts that there’s an official name for it: the female athlete triad. An intimidating term that boils down to three main symptoms: lack of energy, menstrual dysfunction and low bone mineral density 2.

When your energy levels dip too low, even the brain takes notice. According to a 2008 study in Ageing Research Reviews, the pituitary gland sends out fewer reproductive hormones. It’s your body’s attempt to divert energy away from non-essential functions like reproduction and toward more basic survival functions.

When a woman’s reproductive hormones are in flux, it can cause a host of problems. That’s because the main reproductive hormone in women, estrogen, is important for much more than reproducing. It also helps maintain bone density. If a woman doesn’t eat enough, she’ll have trouble keeping her bones strong. And if this level of low-calorie dieting lasts for years, it can lead to osteoporosis.

The thyroid also decreases the hormones it produces during an excessively low-calorie diet. This can lead to weight gain (the opposite of what you're trying to achieve), depression, constantly feeling cold and exhaustion.

Signs Your Diet Has Gone Too Far

But just because you’re not a professional athlete doesn’t mean you’re in the clear. The same thing can happen to any woman who eats too little and exercises too much.

While intense exercise can throw off your reproductive hormones, the bigger concern tends to be eating too little. Low-calorie diets undoubtedly help with weight loss, but it’s easy to take things too far. If you start to notice changes in your cycle, mood swings or low energy levels, it might be time to ease up on the dieting.

Remember: Successful and lasting weight loss is about making small lifestyle changes over time that help you gradually lose weight — not an unhealthy crash diet that forces your body to drop weight too quickly.

It’s important to know the warning signs. Here’s what to watch for:

The first sign that something is wrong is a condition called amenorrhea (the absence of a period). Though lots of things can trigger one missed or delayed period, if it lasts for three months or longer without any other underlying cause, you might be suffering from the female athlete triad, according to an article from the NCAA.

Another baseline measurement is your BMI (body mass index). It’s not the most accurate measurement, but it can give you a rough idea of whether your diet is too extreme.

To find your BMI, find your weight in kilograms (your weight in pounds divided by 2.2). Then, find your height in meters (your height in inches multiplied by 0.025). Take your weight in kilograms and divide it by your height in meters squared. You can also find a calculator online, enter your height and weight and let it calculate your BMI for you. If the number is under 18.5, you might be eating too little.

Start to Up Your Caloric Intake

Fortunately, the problems associated with too low-calories diets stop and can begin to reverse themselves when you begin to eat enough. If you think you might not be eating enough for your activity level or have been diagnosed with the female athlete triad, you should start by slowly eating more food.

According to a study in the American Journal of Physiology, a daily intake of 25 calories per kilogram of lean body mass is a good place to start if you’re eating less than that already.

To figure out how many kilograms of lean body mass you have, use the Boer formula, which takes your height, age, weight and gender and gives you an estimate. The easiest way is to use an online calculator. Once you have your number, divide it by 2.2 to convert it to kilograms. Multiply this number by 25 to get the minimum amount of calories you should eat in a day, as it was calculated as a baseline for people who had decreased their caloric intake to fewer than 800 calories per day.

But if you’re active or eating more than 1,000 calories per day, you’ll need more than this number. To get a more accurate estimate of the calories you should be consuming per day, use an online calculator that figures in your daily activity level. And to track all of this plus your calories and exercise, sign up for a free service like LIVESTONG.COM’s MyPlate.

That might seem like a lot to go through just to find out how many calories you should eat, but being more precise will really pay off. If you don’t want to go through the calculations, you can work with a doctor or registered dietician to figure out how many calories to eat per day to lose weight and still maintain your health.

When you start to eat enough to sustain your body through your workouts, your symptoms should improve. That means your hormones should start to regulate and your periods should resume. Your thyroid should also get back to normal. If it doesn’t, it’s time to go back to your doctor and see if there could be other issues at play.

Balance Your Macros

Beyond a simple calorie count, you can break up your diet by macronutrients. The three macronutrients are fat, protein and carbohydrate. Each is essential to your diet, but you can change how much of each you eat based on your goals.

When you’re losing weight, it’s important to eat enough protein. As the pounds come off, you want to make sure that you’re not losing muscle mass in the process. The best way to preserve muscle is to eat enough protein. Although the recommended daily intake (RDI) for protein for women ages 19 to 70 is 0.36 grams per pound of body weight, some weight-loss experts recommend a higher protein intake if you want to lose a higher percentage of body fat.

Some experts recommend doubling your RDI, consuming about 0.72 grams of protein per pound of body weight. So if you’re a 150-pound female, you should be eating between 54 (your RDI) and 108 grams of protein per day.

Your fat intake can stay at around 30 percent of your daily caloric intake. The amount of fat you consume won’t be as much as protein or carbohydrate, however, since fat is so calorically dense. Each gram of fat has nine calories, whereas a gram of protein or carbohydrate only has four calories. If you’re eating 1,500 calories daily, you should be consuming around 50 grams of fat per day.

After figuring out how much protein and fat you should eat in a day, the rest of your calories can come from carbohydrates. Carbs are a vital part of your diet because they provide energy to your muscles and brain. However, protein is the real priority of a weight-loss diet.