Diet and Weight Loss Tutorial

Eating Disorders
Do you simply need help learning how to eat better? Probably. But if you eat poorly as a result of emotional, mental, or spiritual problems, they may have to be addressed before you can make any real progress with weight loss -- or gain.
If people only ate because they were hungry, we wouldn't hear the term "comfort food" so often. Do you eat for other reasons? The following questions are intended for your consideration only. They are not a test.

• Do you use food to escape your troubles?
• Do you eat when you are not hungry, or not eat when you feel you should?
• Do you eat differently when you are alone?
• Do you have feelings of guilt or remorse about your eating habits?
• Do you give so much time and thought to food that it affects your life?
• Do you always seem to be starting a new diet?
• Do you ever eat and then purge yourself of the food you ate?
• Do you exercise excessively to lose weight?

Types of Eating Disorders
Eating disorders take many forms. Three of the most notable are briefly described here:

1. Compulsive Overeating: Compulsive overeaters usually follow a pattern of binge eating followed by dieting. The dieting phase of this cycle often results in the loss of the weight gained during the bingeing phase, thus the term "yo-yo dieting."
2. Bulimia: Bulimics overeat and then compensate to avoid gaining weight. Methods of compensation include fasting, purging by vomiting or taking laxatives, and excessive exercise.
3. Anorexia: Anorexics have a fear of gaining weight and becoming fat, and often see themselves as being fat. In fact, they are underweight and remain this way by eating too little and using the methods of the bulimic to compensate when they feel they have eaten too much.

Eating disorders interfere with our ability to live a normal life, and they play havoc with our emotional and spiritual lives as well.
Anorexia can lead to the shutdown of body functions resulting in death. The methods used by bulimics have unhealthy side effects and can be very dangerous. Compulsive overeating is not usually thought of as life threatening, but yo-yo dieting is unhealthy and the consequences of being overweight shorten life expectancy and promote disease.

Source: caloriesperhour.com

The Need to Count Calories

Hopefully you will always be interested in the nutritional value of the food you eat, and perhaps from time to time you will be curious about the calories burned by an activity you perform or are considering making a part of your routine. But counting the calories you eat and the calories you burn on a daily basis is quite a different matter.
This website was not created with the intention that you visit it daily for the rest of your life, but rather to help you learn to make healthy choices about the foods you eat and the activities in which you participate.
Today you may need to count calories in order to better understand your eating and exercise habits and make improvements. Or perhaps you find counting calories necessary to help keep things under control. But our lives are always changing, and your needs in this area will change too.
The greater value of counting calories today is what you will learn from the experience. As you learn to eat highly nutritious, low calorie foods and exercise on a regular basis, you will likely find that counting calories is not necessary at all.

Source: caloriesperhour.com

Selecting a Diet Plan

Are you ready to diet? Again? Diets entice us with promises of quick weight loss. But the people we know who eat well and look healthy aren't dieting at all. They have simply adopted good eating habits.
Diets can be so restrictive that they set you up for failure. Some are so low in caloric intake that you literally don't have the energy to continue with them. And while most diets produce quick weight loss at the outset, they often cause your metabolism to slow.
The result is that you have to eat less and less to keep losing weight. You quickly become discouraged, give up, and start eating like you used to. But now, with a slower metabolism, you regain all the weight you lost, and more.

Many Diet Plans Are Designed for Temporary Use and Lead to Temporary Weight Loss

You do not need to join a commercial diet program, purchase special foods or dietary supplements, or use diet pills to succeed at weight loss. In fact, the best thing that you could do would be to start eating healthy right now and continue to do so for the rest of your life.

Of course very few people could do such a thing, so think of a diet or the use of diet aids as tools to help you get started. A good diet plan can teach you how to eat well and give you a jump-start toward meeting your goals.

But whatever path you choose to follow now, your goal should be to make it on your own at some point down the road. Many diet plans are designed for temporary use during weight loss, but only sound knowledge put to practice will provide a permanent solution.

A good diet plan will be healthy from the start, and will be based on principles that you can follow for a lifetime. In fact, if you have found the right diet plan, it will be one that you will want to follow for a lifetime.

Most All Diet Plans Work

Follow almost any diet plan and you will lose weight. This is because whether you are counting calories, fat, or carbohydrates, or restricting certain types of food, you are ultimately restricting the number of calories you consume. The formula for losing weight is very simple: Consume fewer calories than you burn.
So, what should you eat? You would likely do well to eat mostly fruit, vegetables, whole grains, legumes (lentils, dry beans and peas), and limited amounts of lean animal protein (reduced-fat dairy, fish, chicken, and lean cuts of other meats). Also choose whole and natural foods over processed foods whenever possible. Foods with good nutritional value are not only healthy, they help you lose weight.

The above paragraph describes a commonly accepted, healthy way of eating that for most people will result in weight loss and improved health. But there are many diet plans to choose from.

Finding the Right Diet Plan

After learning the fundamentals of diet and weight loss you will be able to choose the diet plan, or simply a healthier way to eat, that is right for you. You will be able to steer clear of marketing gimmicks and promises of short term results, and find a solution based on sound, realistic and healthy principles.
While diet trends come and go, the most basic form of dieting, the low calorie diet, will always be popular. It is based on simply reducing the number of calories you consume. Recent diet trends include the low fat diet and, most recently, the low carb diet. Following this topic you will find:

• The Low Calorie Diet
• The Low Fat Diet
• The Low Carb Diet

In addition, we recommend that you read the following two books:

• Eat To Live by Dr. Joel Fuhrman: A vegetarian-optional diet plan based on eating highly nutritious, low calorie foods.
• Burn the Fat, Feed the Muscle by Tom Venuto: A diet and exercise plan that teaches you how to lose fat without losing muscle and causing your metabolism to slow and weight loss to stop.

Whether or not you choose to follow either of these two diet plans, we believe that reading them will have a positive, lifelong influence on your eating habits, weight, and health.

Take It Easy
Unless you are excited to be following a very specific diet and exercise plan, do not try and change too much too fast. If you have been eating poorly and not exercising, both your body and your mind will have a lot of adjusting to do.
All the sugar and fat were actually quite enjoyable, and sitting on the couch didn't feel too bad, either. If you try and change everything too quickly the odds are greater that you will feel bad, get discouraged, and give up. So be patient.
A time will come when a healthy snack will taste as good as the junk food you felt bad about eating, and you will look forward to your regular exercise.

Source: caloriesperhour.com

The Low Calorie Diet

A low calorie diet can be the simplest form of dieting, nothing more than reducing the number of calories you consume. You could diet on cheesecake, and lose weight! But beware the pitfalls.

A diet based on simply eating smaller amounts of the same highly processed, calorie-rich foods typically results in hunger, poor nutrition, and only temporary weight loss. Eating tiny portions of concentrated, processed calories does not satisfy our hunger. We go off our diets and regain the weight we lost. When we do this again and again, it is harmful to both our health and our self-esteem.

Conversely, by eating foods that are higher in nutrients and fiber and lower in calories, we become satisfied eating fewer calories. We can lose weight even though we are eating more food.

Counting Calories Alone
The caloric value of any diet is the single most important factor for weight loss. The problem with counting calories alone, however, is that while it doesn't eliminate any particular foods, it also doesn't ensure that you are eating a healthy diet.

This is why our food calculator provides data on the three macronutrients: protein, fat, and carbohydrates. It also provides data on fiber to help ensure that you get enough; and on sodium to help ensure that you don't get too much.

The three macronutrients provide most of the calories found in foods. Later in the tutorial you will learn how many calories each macronutrient provides, as well as how to balance them to ensure that you are eating a healthy diet.

Heavily processed foods containing a lot of sugar and other ingredients of little nutritional value are said to contain "empty calories." Because they have little nutritional value, and little if any fiber, they don't keep your metabolism on an even keel like healthy foods do. Thus 500 calories of junk food does not have the same effect on weight loss as 500 calories of healthy food.

In truth, it isn't very likely that you could be successful dieting on cheesecake. Your mom was right when she told you to eat your vegetables; eating healthy foods is the best way to lose weight.

Source: caloriesperhour.com

The Low Fat Diet

The low fat diet became a fad because it was supposed to be good for both your waistline and your health. There is truth to this. However, as we write about the low calorie diet, beware the pitfalls.
Your Waistline

Consider these points:

1. The caloric value of any diet is the single most important factor for weight loss.
2. A gram of fat contains more than twice as many calories as a gram of protein or carbohydrate.

It's easy to see why a low fat diet is good for weight loss. A little less fat means a lot less calories. Plus the fact that most people eat far more fat than is good for their waistline or their health.

But the problem with counting fat intake alone is that while it doesn't eliminate any particular foods, it also doesn't ensure that you are eating a healthy diet. Or even a low calorie diet.

The low fat diet fad filled supermarket shelves with low fat and fat-free products, and you still find many on the shelves today. We are not suggesting that these products are not better for you than their full-fat counterparts, but you need to be careful.

Many fat-free products have been filled with sugar (and salt) to replace the flavor that was lost when the fat was removed. Whatever you're eating, the formula stays the same: Consume more calories than you burn and you will gain weight. So simply counting fat intake won't do the job.

Your Health
While you should limit foods high in saturated fat, fat is necessary to maintain a healthy body. Many people eat too much of the bad fats, but also eat too little of the good fats required for optimal health. So your health is another reason why simply counting fat intake won't do the job.

Conclusion
Many people jumped on the fat-free bandwagon thinking they could eat all the fat-free food they wanted. They gained weight, and their health suffered, too.
Eating less fat would probably be good for most people. But to lose weight, sustain weight loss, and be healthy, you must also be careful about the quality of the food you eat.

Source: caloriesperhour.com

Good Fats and Bad Fats

One of the reasons we love fat so much is that it carries flavor. But if you are trying to lose weight, it is important to remember that a gram of fat contains more than twice as many calories as a gram of protein or carbohydrate. Also, as explained in The Thermic Effect of Food, dietary fat and body fat are so similar that dietary fat is more easily stored as body fat than protein or carbohydrate.

Foods like cheese stand out as among the most fat-laden, with a great number of calories coming from fat. But as important as it is to select the healthiest foods, it is also important to consider how they are prepared.

Fried foods, especially deep-fried, contain a great amount of fat. While chicken and fish are usually leaner than beef or pork, they can contain more fat when they are fried. Look at how the number of grams of fat in a chicken breast changes depending on how it is cooked:
Chicken Breast
Cooking Method Fat
Meat Only, Roasted 3.1
Meat Only, Fried 4.1
Meat and Skin,
Batter Fried 18.5

Be careful with salad dressings, mayonnaise, and other condiments that are high in fat content. They greatly increase the calorie count and can negate the healthy aspects of a meal. Replace mayonnaise-based condiments with fat-free alternatives like fat-free yogurt, mustard, ketchup and barbecue sauce.

Study after study has shown that people living in countries that eat mostly low fat, plant-based diets have lower rates of obesity, heart problems, cancer and many other maladies. But when these people are introduced to the fat-laden Western diet -- either because it is brought into their country or because they move to a country influenced by it -- their rates of these maladies sharply increase.

But don't try to eliminate fat altogether, as dietary fat is necessary to maintain a healthy body. It is a vital component for building body tissue and cells, and it aids in the absorption of some vitamins and other nutrients. Many people eat too much of the bad fats, but also eat too little of the good fats required for optimal health.

Types of Fat
The following paragraphs introduce some of the different types of fat we eat. A high-fat diet typically increases the risk of heart disease and cancer. But a low-fat diet could be even worse if it contained the wrong kind of fats.

1. Saturated Fats: In saturated fats, the carbon atoms contain all the hydrogen atoms they can hold, thus the term "saturated." Saturated fats are usually solid at room temperature.
   Saturated fats are found mostly in animal products such as milk, butter, ice cream, cheese, lard and the fat found on meat. In plants, saturated fats are found in tropical oils such as coconut and palm.
   Saturated fats play the single greatest role in raising blood cholesterol and putting us at greater risk for heart disease.
2. Unsaturated Fats:
   1. Monosaturated Fats: Monounsaturated fats come from vegetables. They remain liquid at room temperature, but become less fluid when refrigerated.
      Monosaturated fats are found in canola, olive and peanut oils, avocados, olives and many nuts and seeds.
   2. Polysaturated Fats: Polyunsaturated fats also come from vegetables, but they remain liquid both at room temperature and when refrigerated. Polyunsaturated fats are found in corn, sunflower, safflower and soybean oils, fish, mayonnaise and many nuts and seeds.
   Unsaturated fats are better for you than saturated fats.
3. Hydrogenated or Trans Fats: Hydrogenated fats are created from unsaturated vegetable fats through a process that adds hydrogen. The process creates trans fats, which are more like saturated fats. They last longer and remain solid at room temperature, making them more marketable.
   Trans fats are found in margarine, many commercially baked goods including cookies, crackers, doughnuts and pastries, and many deep-fried foods and chips. All the bad stuff we love to eat.
   Trans fats raise blood cholesterol, though not as much as saturated fats. They do, however, raise LDL or "bad" cholesterol while lowering HDL or "good" cholesterol. Watch for trans fats on package labels, and where they are not listed watch for ingredients containing partially hydrogenated and hydrogenated oils.
   If you use margarine, note that softer margarines have been hydrogenated less and therefore contain fewer trans fats. Tub margarine is usually better for you than stick margarine because it is less hydrogenated. There are also butter and margarine substitutes available that contain neither cholesterol nor trans fats.
   A food containing no animal products and labeled "cholesterol free" would look like a healthy food to anyone. But look closely. If it contains hydrogenated oils (trans fats), it could be unhealthy for everyone.
4. Essential Fatty Acids: Our bodies require these fats for good health, but can't produce them, so they must be eaten. The primary essential fatty acids are linoleic acid, an omega-6 fat, and alpha-linolenic acid, an omega-3 fat. Most people eat more omega-6 fats than needed and fewer omega-3 fats than are required for optimal health. Omega-6 fats are found in polyunsaturated fats like corn and safflower oils. Omega-3 fats are found in flaxseed, walnuts, green soybeans, tofu and certain fish including albacore tuna, salmon, lake trout, sardines, herring and mackerel.

The actual content of a particular fat is not as clearly defined as these descriptions would lead you to believe. For example, beef fat is listed as saturated, but its actual content is just over half saturated. Olive oil is listed as monounsaturated, but its actual content is just over three-quarters monounsaturated.

Olive oil is so often referred to as being a healthier fat that you might think of it as being healthy. But it is still pure fat, and 14% of it is saturated.

Cholesterol
Cholesterol is a waxy substance that our bodies require for good health. However, excess cholesterol can accumulate on the walls of our arteries and this can lead to heart disease.

Our bodies produce sufficient cholesterol on their own; most of the excess cholesterol in our blood comes from eating other animals. Cholesterol is found in high-fat dairy products, egg yolks, shellfish, liver and other organ meats, and high-fat meats and poultry skin. Plants contain so little cholesterol that they are generally considered to be cholesterol-free.

But What About Eskimos?
Historically, Eskimos have eaten a very high fat, high cholesterol diet. Yet they experienced very little heart disease until introduced to the typical Western diet.

Since their diet was already high in fat, it wouldn't appear to be the high fat aspect of the Western diet that is to blame. Perhaps it is the heavily process foods of the Western diet that contribute the most to disease, for Eskimos and everyone else.

The American Heart Association recommends limiting foods high in trans fats, saturated fats and cholesterol. While there appears to be no debate that trans fats are bad for you, there are those who believe that saturated fats, and even cholesterol, have been unjustly blamed for causing disease only because all fats have been lumped together and labeled "bad."

But it's not that simple. The Eskimo's diet was also high in omega-3 fats, which protect from heart disease. And you can't simply look at total cholesterol, as the ratio between "good" (HDL) and "bad" (LDL) cholesterol can have a significant effect; an increase in HDL may have a positive effect on health despite that fact that it raises the level of total cholesterol.

So there are good fats, and bad fats, and some of the bad fats may not really be that bad under the right conditions. We're sorry it isn't a little less complex. But while all this is being sorted out by science, there is one thing you can count on.

The more you move towards a diet of natural, unprocessed foods, the healthier you will be. Just like the Eskimos and other populations of yesteryear.

Source: caloriesperhour.com

The Low Carb Diet

The low carb diet was first made popular by Dr. Robert Atkins in the 1970s, then became popular once again over 30 years later. It has since fallen out of popularity, but the next diet trend has not yet come along to replace it.

Low carb diets are based on the theory that restricting the amount of carbohydrates you eat will cause your body to burn fat to obtain the energy it needs.

When we eat, our bodies convert digestible carbohydrates into blood sugar (glucose), our main source of energy, which is stored in our liver as glycogen. When we greatly restrict our intake of carbohydrates, to the point where our liver's store of glycogen is depleted and our bodies do not find the usual source of energy readily available, they turn to our fat stores.

Through a process called ketosis, our body fat is "burned" or turned into fuel to provide the energy we need. Our bodies run on ketones instead of blood sugar.

Important Note
It is important to note that if you stray from a low carb diet plan and eat more carbohydrates than the plan allows, it may interfere with the process of ketosis and render the diet ineffective. When confronted with such failures, representatives of low carb diet plans have responded that the dieters are in effect not on the diet plan at all and thus it cannot be said that the diet plan failed.

Net Carbs
Because some carbohydrates are either not digested and simply pass through the body, or are digested but have little impact on blood sugar, some low carb diet plans suggest counting "net carbs" rather than total carbohydrates. Net carbs are calculated by subtracting the carbohydrates that do not affect our blood sugar level (fiber, glycerin, and sugar alcohols) from total carbohydrates.
When available, manufacturer data for net carbs appears in our food lists in [brackets] following the item description.

Are Low Carb Diets Safe?
There is much debate over the long-term effects of low carb diets on your health. While they restrict consumption of carbohydrates, they allow generous consumption of animal protein and fat which have been associated with heart disease and other maladies.
Equally important, many of the foods that low carb diets exclude or greatly restrict have been associated with good health.

Source: caloriesperhour.com

Calories and Kilojoules

Depending on what country you live in, you will find nutrition data listed in calories, kilojoules, or both. Our calculators give you the option of calculating in either calories (kcal) or kilojoules (kJ). If you've never heard of kilojoules, you won't need to worry about them.

A scientific explanation of calories and kilojoules is given in the Technical Notes, below. But for practical purposes, they are a measure of the energy contained in both the foods we eat and our body fat. Our bodies use the energy found in the food we eat to keep us running, and store any excess as body fat for future use.

When we expend energy it is said that we are burning calories, and when we burn more calories than we eat our bodies turn to our fat stores to find the additional energy they require. Thus when we eat more calories than we burn we gain weight, and when we burn more calories than we eat we lose weight.

We have received many letters from people grateful to learn this single point. Confused by the countless rules of countless diets, they entirely missed the single most important fundamental of weight loss. It bears repeating:

Eat more calories than you burn and you will gain weight; eat fewer calories than you burn and you will lose weight.

Balancing Calories

Calories are also used to measure the energy required to perform different activities, including the energy required just to keep our bodies running. It is therefore possible to calculate how many calories you burn in a day, which equates to the number you would eat to maintain your current weight.

If you want to lose weight, you can use the Weight Loss Calculator to calculate how many more calories you need to burn each day than you eat. This figure is called a calorie deficit.

calories eaten - calories burned = calorie deficit

Once you determine the calorie deficit you'd like to achieve, you can use the Food Calculator to calculate how much less you need to eat, or the Activity Calculator to calculate how much more you need to exercise. Or you can achieve the deficit you desire with a combination of eating less and exercising more.

Technical Notes

A calorie is a unit of measure of the energy required to raise the temperature of 1 gram of water by 1°C. A joule is a unit of electrical energy, commonly used in the physical sciences, equal to the work done when a current of one ampere is passed through a resistance of one ohm for one second. Of course we don't use energy to raise the temperature of water or pass current through a resistance, but similar processes maintain our body temperature and perform other bodily functions.

Because calories and joules are so small, when referring to food and energy expenditure it has become common practice to refer to them in multiples of 1,000. The term for 1,000 calories is kilocalories or kcal, and the term for 1,000 joules is kilojoules or kJ.

1 calorie = 4.184 joules

1 kilocalorie (kcal) = 4.184 kilojoules (kJ)

In the scientific and educational communities, it is also common practice to refer to kilocalories as Calories (with an uppercase "c"). However, outside these communities, it has become common practice to simply refer to kilocalories as calories. Therefore when you read 500 calories on a food label it actually means 500 kilocalories, and the same holds true when you calculate an activity that burns 500 calories.

Source: caloriesperhour.com

What It Takes to Lose a Pound

Unit of Weight Approximate Calories Approximate Kilojoules
Pound 3,500 14,644
Kilogram 7,716 32,284


A pound of body fat equates to approximately 3500 calories. So if you have a calorie deficit of 500 calories (meaning that you burn 500 calories more than you eat each day) you would lose approximately one pound per week:

500 x 7 = 3,500

It's easy to see that a calorie deficit of 1000 calories would mean that you'd lose approximately two pounds per week. And that's a good number to remember, because two pounds a week is commonly accepted as the maximum rate of weight loss that is healthy. Losing weight too quickly has other disadvantages, too, and we'll be discussing this in the next topic.

Technical Notes


Body Fat vs. Nutritional Fat

As you will learn in the topic Calories in Protein, Fat and Carbohydrates, it is commonly said that a gram of fat contains 9 calories. But there are 454 grams in a pound, and 9 x 454 = 4086 calories, not 3500.

The reason for the discrepancy is that body fat, or adipose tissue, contains not only fat, but also other substances including protein, connective tissue, and water. The dietary fat referred to in the nutritional analysis of food is pure.

Looking at it another way, 3,500 / 454 = 7.7 calories. Thus a gram of body fat contains only 7.7 calories versus the 9 calories found in pure fat. It's easy to see that there should be a difference when you consider that body fat contains water, which has no calories.

Because of the differences in the two types of fat, it is appropriate to use the 3500 calories per pound figure when discussing fat "burned" by activity, and the 9 calories per gram figure when discussing the nutritional content of food.

Source: caloriesperhour.com

What It Takes to Lose It All

For those planning to attend their class reunion next month, we recognize the need to crash diet with total disregard for health and long-term results. For all others, crash dieting is totally unacceptable. Even if you are headed off to Hawaii and want to look great in your bikini, forget about crash dieting. You won't have the energy to enjoy your vacation.

A good diet may serve you well while you learn to take better care of yourself, but a crash diet will only set you up for failure. The faster you lose weight the more likely you are to put it back on.

Aren't you really more interested in long-term results? Most diets trumpet fast weight loss to get your attention. And your money. But if you lost only a pound a week, that would be 52 pounds a year. Isn't that enough? The slower you lose weight the more likely you are to keep it off.

Spiraling Down to Crash and Burn
Crash diets are called crash diets because they cause you to lose weight quickly. But perhaps a better reason would be because a crash diet will eventually "crash and burn."

Most diets are designed to have you lose a great deal of weight in the beginning to encourage you. But what you lose is mostly water and muscle. The water comes right back when you eat salty (processed) foods again, and losing muscle creates a much greater problem.

Losing more than a pound or two a week can not only be unhealthy, but it will very likely cause you to lose muscle along with the fat. This is bad because muscle is a metabolically active tissue, which means that your body burns calories just to sustain it. Thus losing muscle results in a lower metabolism, the rate at which you burn calories.

With your metabolism running slower and slower, you have to eat less and less to lose weight. And it just keeps getting worse. If you continue to lose weight too quickly for a few days, your body thinks that you are threatened with starvation and goes into survival mode.

Wanting you to eat more, your mind tricks you into thinking you are even more hungry than you are, making it all the more difficult to stay on your diet. And your metabolism is slowed even further to conserve energy. What it tries to conserve is your fat stores, and any weight loss comes at the expense of more muscle.

Finally, you get discouraged, give up, and start eating like you used to. But now, with your slower metabolism, you quickly regain the weight you lost. And if you continue eating like you used to, you end up weighing even more than you did when you started the diet!

Your Goal Should Not Be to Lose Weight

The goal of your diet and weight loss plan should not be to lose weight, but to lose body fat.

Exercise, in particular weight bearing exercise that builds muscle, will help prevent muscle loss and keep your metabolism from slowing. It's also necessary to eat nutritious, well-balanced meals in order to maintain muscle and support all the bodily functions necessary for weight loss.

But the most important factor in any weight loss plan is how many calories you consume each day, and eating too few is the most common mistake.
In the next group of topics, Making Calculations, you will see how some common formulas categorize your current weight and suggest what might be an ideal weight. You will then learn how to use the calculators to determine your calorie requirements to maintain your current weight. And from this figure you can calculate an appropriate calorie deficit.

Creating a Calorie Deficit

To lose weight, you need to create a calorie deficit. This simply means that you need to eat fewer calories than you burn. In his book Burn the Fat, Feed the Muscle, Tom Venuto suggest a calorie deficit of 15-20%. This should be small enough to avoid the starvation response and any significant muscle loss.

For example, if you are currently eating 2500 calories a day, or if you calculate that to be the amount required to maintain your current weight, you could create a calorie deficit of 15% by eating 375 fewer calories a day. Or you could burn 375 more calories a day, or combine eating less with burning more to achieve the 375 calorie deficit.
2500 x .15 = 375
It is important to understand that the results of the calculators are only estimates. They are only intended to give you a place to start. Over time you will learn how your body reacts to the changes you make, and you will make the necessary adjustments to reach your goals.

Weight Loss Calculator
After calculating your daily calorie deficit, you can use the Weight Loss Calculator to estimate of how long it will take to reach your weight loss goal. Choose Calculate Time Required to Reach Goal Weight as the Method of Calculation, enter your Current Weight, Goal Weight, and Daily Calorie Deficit, and the calculator will estimate how long it will take.
Remember that as you lose weight and activity becomes easier, you will burn fewer calories performing the same activities. Because of this, it will be necessary to eat less and/or become more active if you wish to maintain the same daily calorie deficit and rate of weight loss.
Alternatively, you might do better to continue as you are and simply accept the fact that your rate of weight loss will slow as you approach your goal -- and rejoice in your progress.

Source: caloriesperhour.com