Found on: http://my.webmd.com/content/healthwise/4/956 Your weight is affected by three major factors: your genetic inheritance, nutrition, and physical activity. Genetics It is estimated that 30% to 40% of the difference in weight between individuals is due to heredity. Heredity affects basal metabolic rate, appetite and satiety (feeling full), body fat distribution, and possibly the tendency to be active or inactive. - Basal metabolic rate (BMR). BMR determines the rate at which your body uses energy, and therefore, it affects your total energy needs. Some people have higher BMRs than others (based on heredity, height, body composition, and age). A lower BMR makes it easier to gain weight. A person's BMR can change slightly in response to certain conditions. For example, starvation or very low-calorie diets decrease a person's BMR. Overeating increases BMR, as do fever and severe physical stress, such as recovery from surgery or from extensive burns. - Body signals. Hunger, satiety, and appetite are body signals that tell you how much to eat. These signals can be influenced by the environment or ignored for short periods of time. They are powerful drives, and trying to ignore them for a long period of time (as in dieting behavior) can cause you to become obsessed with food. - Set point. Your body tries to keep your weight within a specific range, called your set point. Your body seems to regulate your weight similar to the way it regulates your temperature, blood pressure, and blood sugar (glucose) levels. Research has shown that your body will waste calories if you overeat and conserve calories if you undereat. Your set point range seems to be influenced by your genetic makeup, but your actual weight within that range is influenced by your lifestyle or environment. Your set point adjusts to a new level when it is maintained over time and can be altered by overeating, exercise, some medications, and some brain conditions. There is also a psychological set point. For example, people who are overweight and live with others who also are overweight see themselves that way and are more likely to accept additional weight gain. - Fat distribution. Your weight distribution changes as you age. Aging leads to replacement of lean muscle mass with fat. Men store more fat in the abdomen as they age and women store more in the hips and thighs as they age. Repeated weight loss and gain can change the proportion of fat to lean tissue in your body and actually increase your percentage of body fat. Nutrition Food advertising and the accessibility of fast foods tempt us to eat large servings, often of high-fat foods. In addition, many foods are presented as being better for you than they really are. For example, a low-fat cookie is still a cookie and can't really be considered nutritious. Potato chips labeled cholesterol-free are still high-fat, low-nutrient snack foods. A balanced, healthy diet supplies your body's nutritional needs, satisfies your hunger, decreases cravings, and decreases your risk for some diseases (like colon cancer and osteoporosis). In addition, you will generally feel better, have more energy, and be less likely to gain too much weight if you eat a healthy diet. People who eat regular meals tend to be closer to a weight that is good for them than people who eat on an irregular schedule. Planned meals are usually more nutritious than meals grabbed on the go or at the last minute. Also, skipping meals may make it more likely that you will overeat at the next meal or eat a less-than-nutritious snack. Physical activity Our modern lifestyles require less physical activity than lifestyles of 100 years ago or even a few decades ago, when most people had jobs that required physical labor. We work at jobs that require us to sit all day, and then we watch television at night. We have also created many labor-saving devices, from washing machines to remote controls for the television. All this has led to less than 22% of the United States population getting adequate physical activity. Physical activity is a very important way to prevent obesity and improve health. Regular exercise can improve blood cholesterol and triglyceride levels, reduce blood sugar, and improve other indicators of disease. If you have depression, regular exercise can help lift your mood. It can also boost your self-image and self-esteem. You can be physically fit even if you are overweight or obese. In a study of more than 25,000 volunteers, researchers at the Cooper Clinic found that a person's fitness level was a stronger predictor of death than body weight. Overweight or obese men in this study who were physically fit had a lower death risk than men who were a healthy weight but were not physically fit. Factors that affect children's weight The above factors also affect a child's weight, along with the following: - Mother who had gestational diabetes. Children born to a woman who had gestational diabetes during pregnancy have a greater risk for becoming overweight and for developing diabetes. - Unwillingness to eat foods that they don't like. Children may prefer high-fat foods over vegetables, making a balanced diet difficult and weight gain more likely. They may also think that they don't like a food after having tried it only once or twice. In reality, it takes 8 to 10 times of being offered that same food before a preference is developed. - Family eating patterns or pressures, such as being required to finish all the food on the plate and obtaining food rewards for behavior. When parents control the meal size or persuade a child to eat, the child does not learn to depend on his or her body signals (hunger, satiety, and appetite) for when and how much to eat. Teens are also affected by peer pressure and the cultural influences that promote ultra-thinness. One study found that 59% of the teen girls were unhappy with their body shape, and 66% wanted to lose weight, yet only 29% were overweight. Magazine pictures influenced 69% of the girls idea of the perfect body shape, and 47% wanted to lose weight because of magazine pictures.

The human body weight generally fluctuates in three areas. The first is water. Dehydration can cause a temporary loss of pounds, or kilos of weight, while water retention can cause the opposite effect. Most of the erratic fluctuations in weight throughout the day are just fluctuations in hydration levels. Muscle also influences weight, and can fluctuate, but is usually slow to change. If you do not perform some form of weight baring exercise, the trend is for the muscle to decrease. In fact the average female loses about half a pound (about 0.227 kilograms) each year. Fat can effect the largest swings in weight for many people, and is often what people are actually referring to when talking about weight. Fat levels are influenced by a whole host of factors. The most basic of which is energy input minus energy expenditure. If you are burning more calories then you are taking in then you will lose fat. While if you are burning less calories then you are taking in you will gain fat. Energy input and output are further influenced by other factors still, like metabolism. If you have a high metabolism, then you will burn calories more easily, while if you have a sluggish metabolism then you will burn calories less efficiently. The metabolism is directly affected by many other factors still. An underactive thyroid can slow the metabolism, while an overactive thyroid can increase your metabolism. Other factors are what you eat, when, and how often. The secret to how sumo wrestlers get so big is how they eat. They skip breakfast and lunch. Skipping meals like can dramatically slow the metabolism. Excessive dieting can have the same effect. Also dehydration and lack of sleep negatively affect the metabolism. The metabolism can be increased by frequent meals, (preferably small,) plenty of sleep, and proper hydration just to name a few. But the most dramatic effect on metabolism is muscle. Adding just a few pounds of muscle can speed up the metabolism. It is estimated that a pound of muscle burns about 35 calories a day depending on activity. That means if a person were to add 10 pounds of muscle, they would burn an extra 10,500 calories a month, or the equivalent of 3 pounds of fat. Another very big factor is insulin. Big swings in insulin levels can cause not only fat gain, but problems with insulin sensitivity, leading to syndrome X, and potentially Diabetes. Diets such as Atkins and The Zone are actually designed around the idea of controlling insulin. Sugar and other easily digested carbohydrates cause a big rise in insulin in an attempt to keep blood sugar levels stable. (Look up Glucose Index, or GI for short.) Eating meals high in GI levels will cause an overcompensation in insulin production. The insulin forces sugar into the cells. But at high levels in the body, the insulin will focus that storage into the fat cells instead of muscle and organs, leading to fat gain. Also the overcompensation of insulin will cause low blood sugar leading to hunger, and more eating. There are a whole host of hormones also involved also, probably too many to name, but one of these hormones is leptin. When a person eats their leptin levels rise. Also the fat cells excrete leptin (along with estrogen), so the more fat a person has, the more leptin the body produces. Usually leptin will cause appitite suppression in people, but at real high levels the body begins to ignore this message. Anyone attempting to lose fat weight should follow these rules: Don’t go longer then 3 hours without a meal, except when sleeping. This keeps your metabolism high. Eat lean protein, vegetables, and/or fruit with every meal. Protein slows down the digestion, which helps keeps insulin levels under control. Drink only water. Each week you can eat one meal that violates these rules. Learn to lift weights properly, and lift three to four times a week, taking a week off once every 12 weeks. Add in 1 or 2 days of aerobics, or High Intensity Interval Training (short bursts of very intense aerobic exercise at regular intervals during a longer low level of aerobic exercise,) each week on days you don’t lift. Make sure to have at least one day of no exercise (a day off) each week. Take a few fish oil capsules each day. It decreases cortisol, and triglycerides, and increases insulin sensitivity. Plus a whole host of other benefits. And as far as supplements go, is fairly cheap. (Make sure to eat real fish too.)

Factors that affect weight are : *Food intake *Level of youe physical activity *Basal metabolic rate *Genetic factors *Drugs *Endocrinal health *Age *Sex (Females are more predisposed to weight gain than males)

Mental/emotional factors also affect your weight, often as underlying reasons as to why one overeats and/or doesn't get enough exercise. This could include depression, overcompensation, a sort of co-dependence transferrence (eating a lot after you quit smoking, etc.), blocking thoughts or feelings, trying to fill a void, procrastination, habit, fear of change, etc. etc. I personally don't think that genetics has very much to do with it. My parents are overweight, but I was not born overweight. I became overweight as a child due to my parents' bad choice of food and lack of encouragement to exercise. I acquired the habits and kept them for a long time. But I changed my diet, I exercise 6 days a week, lost a great deal of weight, have never looked or felt better in my life, but my parents are still fat. It's ultimately the mental/emotional factors, which affect how you eat and how active you are, which affects your weight.

Eating a high carb diet (more than 120 carbs per day) increases your weight while eating a low carb diet of 35 carbs per day will cause you to lose 3-7 lbs. per week.

Physical Activity is a very important way to prevent obesity and improve health. Our Modern lifestyles require less and less physical activity in everyday activities. When some people work at a job where all you do is sit around in a chair and then some people work at jobs that involve activity like a gym teacher or a coach for sports. Nutrition plays a very important role in the development of obesity. If you eat to much you are more likely to become obease. When you eat too much fast food again you have a high risk of becoming obease. When you don’t eat at all you would have an eating disorder and you wouldn’t have a high risk of becoming obease. Mental and emotional factors also affect your body weight because females tend to eat a lot when there depressed. Males just tend to eat a lot because there usually bigger than girls and need more nutrition’s to burn when they play sports. Peer pressure plays a HUGE role in the development in obesity because if all of your friends are thin and you are overweight you want to be thin like them and so you go on a crash diet and become sick

For me, just food and exercise. My metabolism is very interesting. After I ate on monday I was 145 lbs, i ran a mile and a half monday, tuesday, and wednsday, and I ate small healthy meals throughout the day. I weighed myself this morning i was 137.

It depends on the individual and their metabolism.

STRESS!!! That is the major cause of weight gain for me. When I am happy I lose weight and when I get stressed or am unhappy my weight goes up.

Definitely STRESS! But the Rolos don't help, either. LOL

what you eat and if you have thyroid issues