Diets to promote weight loss are generally divided into four categories: low-fat, low-carbohydrate, low-calorie, and very low calorie.^[1] A meta-analysis of six randomized controlled trials found no difference between the main diet types (low calorie, low carbohydrate, and low fat), with a 2–4 kilogram weight loss in all studies.^[1] At two years all diet types cause equal weight loss irrespective of the macronutrients emphasized.^[2]

Types of dieting

There are several kinds of diets:

• Weight-loss diets restrict the intake of specific foods, or food in general, to reduce body weight. What works to reduce body weight for one person will not necessarily work for another, due to metabolic differences and lifestyle factors. Also, for a variety of reasons, most people find it difficult to maintain significant weight loss over time. Among individuals that have lost 10% or more of body weight, only 20% are able to maintain that weight loss for a full year.^[3]

• Athletes participating in professional sports may sometimes undertake weight-gain diets to increase their body mass and gain advantage in their field.

• Individuals who are underweight, such as those recovering from anorexia nervosa or starvation, may adopt weight-gain diets which, unlike those of athletes, have the goal of restoring normal levels of body fat, muscle, and stores of essential nutrients.

• Actors, and people participating in similar activities, may pursue weight loss or gain in order to better portray a particular role.

In children and young adults

Receiving adequate nutrition through a well-balanced diet is crucial during childhood and adolescence. Some diets can deprive the body of necessary nutrients, for instance lipids. In addition, there are some indications that the harmful effects of starvation or extreme dieting during adolescence exceed the expected benefits, sometimes even leading to increased weight gains.^[4]

Research shows that putting children on starvation or extreme diets can be harmful. The brain is unable to learn how to correlate taste with nutritional value, which is why such children may consistently overeat later in their life despite adequate nutritional intake. ^[5]

Thermoregulation

As endotherms, humans expend energy to maintain their blood temperature at body temperature, which is approximately 37 °C (98.6 °F). This is accomplished by metabolism and blood circulation, by shivering to stay warm, and by sweating to stay cool.^[6]

In addition to thermoregulation, humans expend energy keeping the vital organs (especially the lungs, heart and brain) functioning. Except when sleeping, our skeletal muscles are working, typically to maintain upright posture. The average work done just to stay alive is the basal metabolic rate.

Physical exercise

Physical exercise is an important complement to dieting in securing weight loss. Aerobic exercise is also an important part of maintaining normal good health, especially the muscular strength of the heart.

Though the energy for muscle activity is primarily derived from the glycogen stored in the body, continued activity results in an increased use of the fatty acids as well. After the available glycogen stores are exhausted, fatty acids alone are used ^[7]. It is often recommended that muscle activity be maintained for 20 minutes or more for increased usage of fatty acids.

The energy burnt during physical exercise has only a limited effect on weight loss, since an hour of aerobic exercise for a man in reasonable physical shape would burn about 2 megajoules (500 kilocalories), which is equivalent to only 60 grams (2 oz) of fat.

Both aerobic and anaerobic exercise would increase the basal metabolic rate (BMR) for some time after exercising. This leads to an additional caloric loss.

Fat loss versus muscle loss

Weight loss typically involves the loss of fat, water and muscle. Overweight people, or people suffering from obesity, typically aim to reduce the percentage of body fat. Additionally, as muscle tissue is denser than fat, fat loss results in increased loss of body volume compared with muscle loss. Reducing even 10% body fat can therefore have a dramatic effect on a person’s body shape. To determine the proportion of weight loss that is due to decreased fat tissue, various methods of measuring body fat percentage have been developed.

Muscle loss during weight loss can be restricted by regularly lifting weights (or doing push-ups and other strength-oriented calisthenics) and by maintaining sufficient protein intake. Those on low-carbohydrate diets, and those doing particularly strenuous exercise, may wish to increase their protein intake. According to the National Academy of Sciences, the Dietary Reference Intake for protein is “0.8 grams per kilogram of body weight for adults.”

Excessive protein intake, may cause liver and kidney problems and may be a risk factor for heart disease.^[8]. There is no conclusive evidence that moderately high protein diets in healthy individuals are dangerous, it has only been shown that these diets are dangerous in individuals who already have kidney and liver problems.

Energy obtained from food

The energy intake from food is limited by the efficiency of digestion and the efficiency of utilization. The efficiency of digestion is largely dependent on the type of food being eaten, while efficiency of utilization is affected by individual factors, including body weight and hormones.

The effects of chewing, especially in elderly people, have been shown to affect the intake of micronutrients. However, there was no significant effect on the intake of macronutrients, such as sugars, fats, and proteins^[9].

Proper nutrition

Food provides nutrients from six broad classes: proteins, fats, carbohydrates, vitamins, dietary minerals, and water. Carbohydrates are metabolized to provide energy. Proteins provide amino acids, which are required for cell construction, especially for the construction of muscle cells. Essential fatty acids are required for brain and cell membrane construction. Vitamins and trace minerals help maintain proper electrolyte balance and are required for many metabolic processes. Dietary fiber is another food component which influences health even though it is not actually absorbed into the body.

Any diet that fails to meet minimum nutritional requirements can threaten general health (and physical fitness in particular). If a person is not well enough to be active, weight loss and good quality of life will be unlikely.

The National Academy of Sciences and the World Health Organization publish guidelines for dietary intakes of all known essential nutrients.

Sometimes dieters will ingest excessive amounts of vitamin and mineral supplements. While this is usually harmless, some nutrients are dangerous. Men (and women who don’t menstruate) need to be wary of iron poisoning. Retinol (oil-soluble vitamin A) is toxic in large doses. As a general rule, most people can get the nutrition they need from foods. In any event, a multivitamin taken once a day will suffice for the majority of the population.

Weight-loss diets which manipulate the proportion of macronutrients (low-fat, low-carbohydrate, etc.) have not been found to be more effective than diets which maintain a typical mix of foods with smaller portions and perhaps some substitutions (e.g. low-fat milk, or less salad dressing).^[10] Extreme diets may, in some cases, lead to malnutrition.

How the body gets rid of fat

All body processes require energy to run properly. When the body is expending more energy than it is taking in (e.g. when exercising), the body’s cells rely on internally stored energy sources, like complex carbohydrates and fats, for energy. The first source the body turns to is glycogen (by glycogenolysis). Glycogen is a complex carbohydrate, where 65% of it is stored in skeletal muscles and the rest in the liver (totaling about 2000 kcal in the whole body). It is created from the excess of ingested macronutrients, mainly carbohydrates. When those sources are nearly depleted, the body begins lipolysis, the mobilization and catabolism of fat stores for energy. In this process, fats, obtained from adipose tissue, or fat cells, are broken down into glycerol and fatty acids, which can be used to make energy. The primary by-products of metabolism are carbon dioxide and water; carbon dioxide is expelled through the respiratory system.

Fats are also secreted by the sebaceous glands (in the skin).

Psychological aspects of weight-loss dieting

Diets affect the “energy in” component of the energy balance by limiting or altering the distribution of foods. Techniques that affect the appetite can limit energy intake by affecting the desire to overeat.

Cognitive Behavior Therapy has been effective in producing long term weight loss ^[11]. Judith S. Beck has been one of the most prominent practitioners and writers to bring this method to a popular audience.

Consumption of low-energy, fiber-rich foods, such as non-starchy vegetables, is effective in obtaining satiation (the feeling of “fullness”). Exercise is also useful in controlling appetite as is drinking water and sleeping.

The use of drugs to control appetite is also common. Stimulants are often taken as a means to suppress hunger in people who are dieting. Ephedrine (through facilitating the release of adrenaline and noradrenaline) stimulates the alpha(1)-adrenoreceptor subtype, which is known to act as an anorectic. L-Phenylalanine, an amino acid found in whey protein powders also has the ability to suppress appetite by increasing the hormone cholecystokinin (CCK) which sends a satiety signal to the brain.

Weight loss groups

There exist both profit-oriented and non-profit weight loss organizations who assist people in their weight loss efforts. An example of the former is Weight Watchers; examples of the latter include Overeaters Anonymous, as well as a multitude of non-branded support groups run by local churches, hospitals, and like-minded individuals.

These organizations’ customs and practices differ widely. Some groups are modelled on twelve-step programs, while others are quite informal. Some groups advocate certain prepared foods or special menus, while others train dieters to make healthy choices from restaurant menus and while grocery-shopping and cooking.

Most groups leverage the power of group meetings to provide counseling, emotional support, problem-solving, and useful information.

Food diary

A July 2008 study, published in the American Journal of Preventive Medicine, showed dieters who keep a daily food diary (or diet journal) of what they eat lose twice as much weight as those who do not. The researchers concluded, “It seems that the simple act of writing down what you eat encourages people to consume fewer calories.”^[12] Diet journaling software and websites have become popular to help people track calorie consumption, calorie burning, weight loss goals, and nutritional balance.

Obesity is the second leading cause of preventable death in the U.S. ^[1]

Want to slim down fast for that beach vacation or high school reunion? While there are many things you can do to shed pounds, losing weight too quickly, like any sudden change to your body, can be dangerous. While fad diets, diet pills, and fasting may indeed induce rapid weight loss, these methods can cause you to lose muscle and may also injure your heart and other organs fairly quickly. The best solution? Don’t go for an overnight miracle. Instead, follow these steps to lose fat rapidly, healthily, and sustainably.

Steps

1. Determine your daily calorie intake . Losing weight is simply a matter of expending more calories than you take in, through exercise and your daily activities. To win the battle, it helps to know how many calories you are consuming in a day.
   • Write down all the things you eat on a typical day. Carry a small notebook with you and write down every snack, every drink, and the contents of every meal. There are also great websites that you can use to keep track of calories, get recipes, and help achieve your goal. Don’t forget to include the pats of butter or the spoonful of sugar in your coffee. It’s best to do this for at least a couple weekdays and a weekend; it’s even better if you can go a full week. There are also calorie tracking websites that can help you to do this, for example the US government website, My Pyramid Tracker.
   • Do an itemized calorie count. When possible, write down the number of calories in each thing you eat as you eat it. Keep in mind that the recommended serving size is often considerably smaller than the serving you actually eat. Look up the calorie count on the internet for foods that don’t have calories listed on the container or for fast food meals. You don’t have to be 100% accurate, but you do want a good estimate of the number of calories you’re taking in. There is an idea that multiplying your own weight by ten will produce a rough estimate of the number of calories you need to eat per day to maintain your weight. This is NOT true, you may wind up grossly under (or perhaps over) estimating the number of calories you should be eating. Use a scientific or health website to determine the number of calories you should eat a day or consult your doctor. Everyone has different metabolisms and there is no blanket rule that covers everyone’s recommended calorie intake. Reducing 500 calories per day from the calories you eat to maintain your weight can help you lose a pound of fat per week.^[2]
2. Go over the list and decide which foods to cut out or reduce. Cutting calories is usually a lot easier than you might think. For example, that daily tall latte in the morning may pack 500 calories. Since a pound of flab (lost or gained) is roughly equivalent to 3,500 calories, replacing that rich beverage with black coffee can help you lose a pound a week. Other easy cuts include salad dressing (salad dressing is the number one source of fat in the average American woman’s diet) soda pop, candy, and butter. Look at the nutritional information for the foods you eat, pay special attention to your intake of saturated fats and empty calories (high-sugar foods). You don’t need to cut these things out entirely, but if you reduce your intake of high-fat, high-calorie foods you’ll lose weight faster.
3. Seek out alternatives to the unhealthy foods you’ve identified. You can simply reduce the amount of soda you drink or mayonnaise you put on your sandwiches, or you can substitute healthier choices. Drink water instead of soda, for example, or use mustard instead of mayo. Low-fat and low-calorie options are also available for most foods, and many of these are natural, (although some are made with strange chemicals), and tasty. Start trying to eat healthy in most meals:
   • Choose lean meats. Chicken and fish are both very low in fat (and certain fish like salmon, sardines, and fresh tuna are an excellent source of antioxidants, which are also beneficial to your health), so aim to replace some or all of the beef or pork in your diet with these foods.
   • Replace high-calorie side dishes with healthier alternatives. Many people get a ton of calories from side dishes such as macaroni and cheese, French fries, or potato salad. You can eat healthier and lose weight by replacing these with fresh vegetables and salads. Pre-made salads are practically effortless, and when accompanied by a reduced-calorie dressing or no dressing at all, they’re weight-loss gold.
   • Start your days off right. A fattening breakfast of bacon and eggs or a pastry can be replaced with yogurt, oatmeal, high-fiber, low-sugar cereals; or fresh fruit for fruit smoothies. However, for those on a low carb diet bacon and eggs are a great combo for breakfast, since neither have carbs. But don’t fall into the trap of skipping breakfast. Eating a healthy breakfast increases your rest metabolic rate earlier in the day, and reduces snacking before lunch.
4. Plan your meals. Look for healthy, delicious meals online or in your cookbooks, and create a menu for the week. Make sure that your meal plan reduces your total calorie intake: you’re not going to lose weight if you consume the same amount of calories by eating different foods. Make a list of what you’ll need for these meals, and — except for a few snacks, of course — don’t stray from your list when you get to the market. Planning your meals helps ensure you get a balanced diet and reduces the temptation to stop off for fast food or order a pizza. Remember, it’s easier to stick to your shopping list if you shop when you aren’t hungry.
5. Watch your portion sizes. Opening a bag of rice cakes and eating all of them in one sitting isn’t going to help you lose weight. When eating chips, nuts, or dried fruit put a portion in a small bowl and then put the bag away. That way you won’t mindlessly eat a larger portion than you had intended. Even if you only make minimal changes to your diet choices, reducing portion size will inevitably reduce caloric intake. A great way to watch portion sizes while snacking is to buy one serving 100 calorie packages – and they come in many favorite snack food items!^[3]
6. Graze on healthy snacks. Just because you’re getting healthy doesn’t mean you can’t snack. In fact, eating small meals and snacks throughout the day, or grazing, has been shown to aid weight loss, (compared to eating three large meals a day), by keeping metabolism steadier. Pick snacks that are low in calories and fat and high in fiber (dried apricots, nuts, rice cakes, fruits, baby carrots, cherry tomatoes, and so on). Vegetables are generally very low in calories, very high in fiber, and full of flavor and nutrition. Avoid starchy vegetables like potatoes, and try to eat vegetables plain, without fatty dressings or dips. Fruit also makes a good snack. Fruit contains more soluble fiber than vegetables, which slows your body’s absorption of carbohydrates, thus releasing energy more slowly, (preventing sugar highs), and keeping you feeling full longer. Fruit juices are not a replacement for the real thing. You need that fiber, and juices often have more calories than the equivalent serving of fruit — as many calories as soda! Be careful with dried fruits, because without the water, you tend to eat more, and fruits, when dried, are calorie-rich per ounce. With any dry or dried food, be sure to drink plenty of water.
7. Get more fiber. There are many myths about fiber, but there is science to back up its helpful role in the diet. Fiber keeps the right amount of water in your intestines, making your digestive system work more efficiently and helping to keep you regular. Thus, just eating enough fiber may help you feel slimmer in just a day or so. There is also evidence that fiber in the diet can help prevent stroke and heart disease, ease the effects of diabetes, and may even directly help in weight loss.
8. Drink plenty of water. Adequate water is essential for health, and a great many people simply don’t get enough. What’s more, if you’re chronically dehydrated, your body will retain water in unflattering places, so if you make sure to get plenty of fluids you can start visibly trimming down in as little as a day. Remember, the more you exercise, the more water you’ll need. See the related wikiHow for more details on how much water you should be getting.
9. Exercise. Remember, you can lose weight either by decreasing your calorie intake or increasing the number of calories you burn. Any health strategy should include both, but if you want to lose weight fast, exercise is essential.
10. Perform high-level aerobic activities. Moderate aerobic workouts incorporating jogging, brisk walking, cycling, aerobic machines, or classes not only burn calories — they also keep your heart healthy. Swimming is also great, especially if you are quite overweight or have joint problems, because you can get the same benefits of running — typically burning even more calories — with much less stress on your joints. Try to get at least 30-40 minutes of aerobic exercise at least three or four days per week.
11. Pump some iron. Resistance training, (weight training), can help both sexes stay lean by building muscle and raising metabolism. The fact is, hours and hours of aerobic exercise won’t help most people lose weight fast because your metabolism drops back to normal fairly quickly after stopping the exercise. If you gain muscle, however, your body’s resting metabolism, (the amount of calories you burn when you’re just sitting still), increases, because muscle requires a lot of calories to maintain. Studies have shown consistent weight training to raise the body’s metabolism by 15%. This means an average woman might burn 200-300 more calories at rest every day! Resistance training is the gift that keeps on giving! Although, keep in mind that muscle mass weighs more than fat (don’t be surprised if you gain weight but look slimmer).
12. Rest properly. This means not only taking at least 24-48 hours between strength training the same muscles, (and taking 1-2 days off from exercising each week); it also means getting enough sleep at night, since sleep deficiency impairs your ability to lose fat.
13. Be realistic. Don’t expect a miracle. Healthy weight loss can be achieved fairly quickly, but you’ll need to be patient. In addition, be sure to set realistic goals. Make sure that the weight you’re trying to reach is a healthy weight for you, and keeping in mind that gaining pounds of muscle will help you lose fat, be trimmer, and look better even though you don’t actually lose any weight. Your goal should be a healthy body, not a number of pounds! Everyone looks good at a different weight. A short person may look really good at about 112 pounds, but a person of a taller height would just look unhealthy. Keep yourself at a weight that makes you look good, not at a number that sounds good.
14. Make adjustments. A successful weight loss strategy based on reducing calorie intake and increasing activity can be adjusted to maintain your desired weight once you reach it. Unlike typical diets, this method is sustainable — it is a lifestyle change, not a binge-and-purge exercise. Slowly adjust your diet and exercise to include more weight training and calories, as much as is comfortable for you. If you do gain any weight back, you want that weight to be lean, toned muscle, not fat. In addition, weight training, no matter what your age, prevents muscle atrophy and can help stave off osteoporosis.
    • Instead of thinking of it as losing a certain amount of pounds, think of it as being a certain weight. So if you are 145 pounds, and you would like to lose 10 pounds, think of it as being 135 pounds. This helps you think about it as a long-term goal and not just losing the weight to gain it back again.
15. Be confident. You need to believe in yourself! If you want to diet, and you know that it will make you feel better, then you need confidence. Otherwise, the temptation to cheat on your diet will make it harder, and you will not feel better when you do lose weight. Avoid temptations like chocolate, ice cream, and cookies. They may taste good, but there are other foods that taste delicious, too, without being unhealthy. You need to always encourage yourself to achieve the goals that you have set. Learn to evaluate your efforts fairly and objectively. If you fail to achieve your target for the week, find out why is it so. Is it because you have missed a jogging session? Or you have been eating junk food for one of the days? After evaluating, look ahead to next week and try your best to stick to your plan.^[4]
16. Be consistent and disciplined, and have self motivation. To lose weight effectively, you need to stick to your weight loss plan religiously so as to see results. When you have the thought of giving up, visualize how good you will look when you manage to slim down successfully. ^[4]

Right now Oprah Winfrey just announced that she has gained much of her weight back.
After years of dieting and having her own people, like her chef Rosie, ( I have this book, and the recipes are very good!)



Even Oprah, with all that money and resources has gained back part of her weight and struggles to keep it off. She even has her own trainer!

6. Keep a food journal, ( another thing I always start but never stick too!)
Studies have proven people who wrote everything down, ate less and had better success at changing
their eating habits. I have been using fitday for years , it is free and I can look back at the last 7 New Years and see the same 10 pound resolution I have made all this time in my online journal there.


Hang in there, stay positive and remember, you only have one life and you can change and make it what it you want to be. Just start small, and keep building up positive actions, one small thing at a time. Try to make just a few changes, and pat yourself on the back as you make them.
Be proud of yourself for each step you make towards change. Change is hard and a lifetime of habits takes time to undo. It seems women especially are so hard on themselves. Please start your day off with some positive affirmations about yourself and what you want out of the day. This can change your whole day. Take that time for yourself, you need it. Best of luck and Happy New Year!