Last Update: March 8, 2012.

Being overweight increases the risk of health problems, but what benefits can you expect if you lose weight? Is there an immediate health pay-off, or is it impossible to get quick results? Losing weight and then keeping it off usually takes a lot of motivation, because we really have to change our lifestyles if we want to change our weight for the long term. Changing long-established habits and patterns of behavior is hardly ever easy.

If we want to lose weight, not achieving our goals can make us feel quite bad about ourselves. Being a normal weight is important for our health, but that is not the only issue for many of us. Our society places great importance on how we look. This is why we can become unhappy or even depressed if we feel unattractive because of our body size. On the other hand, there is also the view that overweight people just enjoy life and have more fun than other people. Contradictory messages like this are common when it comes to weight and weight loss. So what happens emotionally when you lose weight? How many of your problems could losing weight solve?

Unfortunately, despite all the claims about weight and weight loss, there are not many reliable answers to these questions. But some of the research could help you find your way through the maze of claims and counter-claims about weight loss.

How much weight do you need to lose to get healthier?

Firstly, you do not have to lose weight if you are not genuinely overweight. And even if you are, weight is not the only important issue, either. What is actually most critical is the amount of fat in your body, and where that fat has built up. Muscle, for example, is quite heavy. So if you gain weight because you have increased your muscle bulk, the extra bit of weight is no problem at all.

Two approaches are commonly used to determine if people are overweight: the body mass index (BMI) and waist measurement. The BMI helps to determine how much you weigh in relation to your height. Waist measurements give you an idea of how fat is distributed in your body.

The BMI is the most common way to try to work out if people are overweight or very overweight (obese). It measures the relationship between weight and height. People who have a BMI over 30 are considered to be obese. Being obese is a greater risk to health than being overweight. People who have a BMI between 25 and 30 are usually considered to be overweight. Being overweight alone does not necessarily cause health problems, but it could be a problem if the person already has certain illnesses, such as type 2 diabetes.

The BMI scale cannot always be used in this way because, for example, a certain BMI is associated with different health risks in people from South Asia compared to people from Europe. The same is true for waist measurements. A waist measurement of 88 cm or more could put European women at a higher risk of health problems, while for European men, more than 102 cm could be a sign of increased health risks. This is also true even if their weight is within the normal range.

You can get a better idea of how fat is distributed in your body by looking at the relationship between your waist and your hips. If you have a relatively big amount of belly fat, your risk of disease is higher. A more "apple-shaped" person with a "beer belly" and narrow hips faces higher health risks than someone who does not have much fat stored around their belly. Abdominal (belly) fat in particular increases your risk of heart disease. If your body fat tends to be stored around your legs, hips and bottom rather than your belly, then it is less likely to be a health problem. This is often called being "pear-shaped", because you are smaller on the top and rounder lower down.

Being too worried about your weight can itself become a problem. If you are not in fact overweight, but keep losing weight, then you could quickly become unhealthy.

Are there any quick health results that I can get from losing weight?

Being overweight or obese increases your risk of long-term health problems that could shorten your life, like diabetes and cardiovascular disease. Preventing these serious illnesses is often the main health reason why people try to lose weight if they are obese.

Reducing your risk for serious life-threatening illnesses is an important health benefit. Many people may feel that the best reward for losing weight is feeling healthier and seeing an improvement. One of the first benefits you might notice is having more energy. If you are losing weight with the help of exercise, your fitness will be increasing. So you could quite quickly be able to climb more stairs without getting out of breath, for instance.

If you have osteoarthritis in the knees, you are likely to experience a quick improvement there, too. Being overweight or obese puts a lot of stress on your knee joints in particular. If you have been overweight for a long time, your risk of osteoarthritis will increase quite a lot as well. Losing weight can prevent you from developing osteoarthritis of the knee joints. If you already have painful knees, losing weight can relieve the symptoms.

If you are obese and you have osteoarthritis in your knees, you are likely to notice that you can move your joints more easily if you manage to lose 10% of your body weight in three months. But even if you only lose 5% of your body weight in five months, you could still feel a real difference in what your knees can do. If you are 80 kg (about 177 pounds), then 5% of your body weight would be 4 kg (about 9 pounds). You can read more about the positive effects exercise and losing weight have on osteoarthritis here.

One of the other important health benefits of losing weight may be that your doctor might decide that you can take less of the medication you have been taking, or stop taking it altogether. This may include drugs to lower your blood pressure or cholesterol level, insulin for type 2 diabetes, and other drugs to lower your blood sugar.

Of course, how you lose the weight also matters: there are healthy and unhealthy ways to lose weight. Some weight-loss drugs have adverse effects that can harm some people’s health. One drug, rimonabant (brand name: Acomplia) had its license for use in Europe suspended by the European Medicines Agency (EMA) in October 2008 because it had caused serious depression. And in January 2010, authorization for the drug sibutramine was suspended by the same agency. They had determined that the potential benefits of sibutramine did not outweigh the possible harmful effects, particularly cardiovascular disease.

The U.S. regulatory agency FDA ruled in May 2010 that all medication containing orlistat, also available over-the-counter in low dosage, must include a warning about serious liver injury as part of its package insert in the United States. There had been individual cases of this in people who had taken, among other drugs, orlistat. Yellowish skin, itchiness, noticeably darker urine, light-colored stool and upper-abdominal symptoms can all be signs of damage to the liver. The agency recommends suspending the use of medication and consulting a doctor if these symptoms occur.

The latest diet craze in women's magazines will probably not give you the results you want either. Generally speaking, you lose weight by reducing how much energy you consume (calories from fat and carbohydrates in food) and by increasing how much energy you use (by being more active). If you lose weight but smoke more, the smoking could do more harm to your health than a few kilograms of extra weight will.

How can I keep the weight off permanently?

Losing weight is hard enough, but keeping it off for the long term can be even harder. To keep weight off permanently, you need to have made some real and sustainable changes to your lifestyle. Because your previous habits led to your being overweight, going back to those habits means the weight would be quite likely to return. This means that it is important to find new habits that you can really live with for the long term: for example, a form of exercise that you really enjoy, or that is at least very practical for you to keep up.

One of the main things you can do to keep your weight down is to exercise, as well as change your eating habits. Researchers have found that when people who are overweight or obese lose weight with a combination of diet and exercise, they lose on average 20% more weight than if they only diet. For the people in that research, this meant an average of 3 kg extra weight loss due to exercise. And this improvement also held over the longer term: a year later, the people who had exercised still weighed less than the people who had only dieted.

It is believed that people really need to be getting at least 30 minutes of moderate-intensity exercise on at least five days a week to stay healthy and fit. "Moderate-intensity exercise" means doing something that increases your heart rate. This means that walking very slowly does not count, but walking briskly does. You do not have to exercise so strenuously that you are out of breath, but you do need to exert yourself at least a little to get a benefit.

Brisk walking has been shown to help very inactive people get more exercise into their everyday lives. People who work full-time, for example, would get the recommended 30 minutes of exercise by walking at a fairly brisk pace for 15 minutes to and from work every day. Regular brisk walking has many advantages, such as not needing special equipment and causing fewer injuries than many other forms of exercise.

People who walked on average an extra three hours per week for eight months were able to lose around one kilogram and two per cent of their body fat through the walking alone. They improved their cardiovascular fitness (the strength of their heart and circulation) and there was a small positive impact on their blood pressure. You can read more about that research here, and about ways that can help people walk more here.

How can I keep motivated?

If you are having trouble losing weight and keeping it off, then getting support from your doctor or someone else who encourages your progress could help.

It is important that the changes you make are suited to your physical fitness and your state of health. Your doctor can help you consider the options. The key to long-term success is to find ways that are practical for you. You may have to explore several options before you find something that works. If you have already lost weight but get stuck at some point, you might need to try something new to start making progress again.

It is important not to give up completely, even if you do have setbacks or some difficult times. Seeing a reduction in your waist and losing weight is probably the best feedback to motivate yourself, but it can also be disheartening if nothing is changing.

Some people watch their cholesterol levels as a sign of whether their risk of heart disease is going down, but this is not always a guarantee that your health risks are decreasing. Nevertheless, it can be very encouraging to see measurements like your cholesterol or blood pressure fall.

The health risks that come from being overweight are a combination of many factors. This means that health interventions do not necessarily have an immediate effect. For example, losing weight might not always be enough to reduce your blood pressure in the short term. You can read more about the research on this here . So, just because you are not seeing immediate results, it does not mean that it is not worthwhile to stick with your new habits.

IQWiG, the publisher of this website, is looking for research that shows ways of reducing your blood pressure without drugs. We will update this information as the IQWiG's assessments become available. 

What if I am losing weight but it does not make me feel as good as I expected?

Many people who lose weight will feel better physically and emotionally. But even if you do not feel better or are disappointed with the results you have achieved, the weight loss could still be making you healthier.

Other ways of losing weight might make you feel happier about yourself. For example, some people feel better with the support they get from a group of others who are also trying to lose weight. Others feel better if they go to group sessions that help them to learn to accept their bodies and improve their body image. Doing regular exercise gives some people a lot of satisfaction and makes them feel emotionally better, but not everyone experiences this.

Losing weight is not the only way to improve your health. Getting more exercise, even if it is not reducing your weight, can also have other benefits for your well being. You can feel good about yourself and be healthy even if you are not a normal weight for your height. Getting to know your body and accepting yourself might be more important for your happiness than losing weight.

Some people will have thought for a long time, “I'll feel much better and happier if I just lose some weight . . .” So if they do not end up with the results they had hoped for when they lose weight, they may feel very disappointed. Even though being overweight can cause a lot of problems in your life, the weight itself might not be responsible for all the problems that you think it is. This means that losing weight will not necessarily solve all your problems. Expecting life to become easier by losing weight alone is unrealistic.

It is difficult to lose weight and then keep it off. If you have been able to do it, it is an important achievement. Having done it, you may also find that you are better able to take on other challenges and succeed with them as well.

Author: Institute for Quality and Efficiency in Health Care (IQWiG)