Weight loss programs and medications

Photo of an overweight family on a walk

Weight loss recommendations for obese people include a combination of changing their diet, getting more exercise and changing certain behaviors. Many weight loss programs have these elements in them. Treatment with medication is sometimes considered as well. Very unbalanced weight loss diets can harm your health.

Your body’s basal metabolic rate (the energy it needs to keep up basic functions) makes up about 70% of your daily energy needs on average. Physical activity uses up less energy. The calories in your food and drink have a bigger influence on your body weight than physical activity does. As a result, it's hard to lose enough weight if you don't change your diet.

When it comes to losing weight, the main rule is to take in less energy than you burn. The types and combinations of foods in your diet don't make a difference here. Doing exercise and sports on top of that can make it easier to lose weight and also have a positive effect on things like high blood pressure and diabetes.

What role do carbohydrates, fats and proteins play?

Some diets have very few carbohydrates or fats in them. Others focus on getting a lot of protein. These diets can be difficult to follow in everyday life because you have to avoid a lot of foods. An analysis of studies comparing different weight loss programs also showed that it doesn’t make a big difference if you eat a low-fat diet or a low-carbohydrate diet.

These types of diets can also be too unbalanced and have side effects. In one study, for example, a very high-protein diet caused more gastrointestinal (digestive) problems and bad breath. The participants also felt weak, and had muscle cramps and rashes more often.

For these reasons, experts generally don't recommend one-sided diets. Instead, they recommend changing your diet in a way that is realistic and achievable for you personally, and that can help you keep your weight down over the long term. For example, some people find it difficult to eat fewer animal products like meat and cheese (fatty foods), while others have a harder time cutting down on pasta, rice and potatoes (carbohydrate-rich foods).

Plus, completely avoiding certain foods often isn't practical in everyday life – for example, during family meals or when eating out. In other words, reducing calories in your diet is a good way to lose weight if the diet is doable for you personally and you can stick to it in the long term. Of course, the diet shouldn't pose any health risks or lead to malnutrition.

Which weight loss programs are recommended?

Various weight loss programs have been developed, and some of them have been scientifically tested. A weight loss program should include changes to your diet, the amount of exercise you get, and certain other behaviors. The idea is to

  • change habits, for instance when grocery shopping,
  • learn to pay attention to what you eat,
  • create a flexible, doable diet and exercise plan, and
  • set realistic goals.

Various programs are available in Germany. For example:

  • Abnehmen mit Genuss ("Enjoyable weight loss") is offered by the statutory health insurer AOK. Based on making changes to your diet and exercise habits, it can be used online on a computer, through an app, or in a paper-based form. You also receive support and related advice through the same channels. AOK members are fully or partially reimbursed for the costs of the program.
  • Bodymed is mostly offered in doctor’s offices. The program runs for twelve weeks and involves replacing two meals a day at first – and then one meal a day – with formula nutrition (protein shakes and bars). The program also includes advice on nutrition and exercise, to help you change your diet in the long term and keep the weight off.
  • Ich nehme ab ("I'm losing weight") was developed by the German Nutrition Society (DGE, Deutsche Gesellschaft für Ernährung). A list of providers can be found on the DGE website. This program uses various materials, such as a cookbook and a food and exercise diary. You can also do the program on your own without extra support, but studies have shown that this is less effective.
  • Weight Watchers uses a system with points. The basic idea is that you are allowed to use up a certain number of points each day. The number of points for each food mainly depends on the number of calories in it, and also what's in it. You can “earn” additional points by being physically active, and use those points to eat more. You can participate online (using a computer or an app) or go to in-person meetings.

The following programs are particularly suitable for people with a of 35 or more:

  • M.O.B.I.L.I.S.: Various statutory health insurers support this program. It includes group sessions and courses on exercise, diet and changing your behavior, with a focus on getting more physically active. The program lasts for one year. Some health insurers cover a part of the costs.
  • Optifast-52 is a program that involves dietary advice, exercise and behavioral approaches. It starts with a one-week preparation phase. This is followed by a twelve-week diet where all meals are replaced with protein-rich formula food. Over the next six weeks after that, you gradually switch back to solid food again. The rest of the one-year program aims to stabilize your diet and body weight over the long term. The program takes place in groups, and includes support from experts working in the fields of healthcare, nutritional sciences, psychology and sports science.

When deciding which program to do, your starting weight, target weight and personal preferences will play a role – for example, if you would rather attend an in-person program locally or join an online program to better suit your everyday life.

The cost will play a role too. Many health insurers reimburse some of the costs of certain programs. Contact your health insurer to find out more about this.

What can you expect from these programs?

In studies, people who did weight loss programs like Weight Watchers lost between 3 and 8 kilos within six to twelve months. The average amount of weight lost was about 5 to 6 kilos.

Research has found that programs using formula food led to greater weight loss of about 10 to 15 kilos.

Studies suggest that online weight loss programs (accessed through a computer or app) are effective, too. But there isn't enough research to say whether they’re as effective as programs that include personal contact or group meetings.

How does additional exercise help?

Getting more exercise can be a helpful addition to changing your diet. It can help you lose more weight. Research has shown that physically active participants lost almost 2 kilos more within 12 months than those who only changed their diet. Their activities consisted of 30 to 45 minutes of moderate physical exercise (like brisk walking) three to five times a week.

Physical activity has many other health benefits, too. It improves your fitness and has a positive effect on risk factors for cardiovascular diseases, like blood pressure. Sports can also add variety to your daily routine, improving your quality of life and helping to clear your head.

But research has also shown that you usually can’t lose enough weight by exercising more if you don't change your diet as well. It is almost impossible to lose a significant amount of weight without changing your diet.

When are medications considered?

If you can’t lose enough weight by changing your diet, getting more exercise and changing certain behaviors, you might be advised to use medication that needs to be prescribed. In Germany, the drugs orlistat and liraglutide have been approved for the treatment of obesity.


Orlistat inhibits fat-digesting enzymes (lipases) in the small intestine. As a result, there is less fat for the body to absorb. People who use orlistat can expect to lose about three percent of their body weight over the course of one year. So someone who weighs 130 kilos could expect to lose about 4 kilos in one year.

The medication is taken three times a day with meals and a glass of water. The tablet can also be taken up to one hour before or after a meal. Treatment with orlistat should be stopped if your weight doesn’t change within 12 weeks. Some people are advised to take orlistat for longer, so they don't gain weight again.

The possible side effects of orlistat include soft, oily stools, the frequent urge to empty your bowels, and bloating due to gas in your gut. Bloating can be painful and make your tummy rumble or gurgle. These side effects occur in about half of all people who take orlistat. They are severe in less than 1 out of 100 people. In studies on orlistat, 8 out of 100 people stopped the treatment early due to side effects.

Orlistat is not suitable for people who are breastfeeding, have chronic food absorption problems in the bowel, or an obstructed bile duct. If the medication causes diarrhea, it might reduce the effectiveness of the birth control pill. Other medications could interact with orlistat too. It is best to talk with your doctor about whether orlistat is an option for you.


Liraglutide (trade names: Saxenda and Victoza) is injected once daily under the skin, for example into the belly or thigh. It makes you feel full and less hungry. People who use liraglutide can expect to lose about five percent of their body weight over the course of one year. So someone who weighs 130 kilos could expect to lose about 6.5 kilos in one year. To make the medication easier to tolerate, its dose is gradually increased over the first four weeks.

The possible side effects of liraglutide include nausea, diarrhea, constipation, vomiting and belly ache. These side effects occur in about 75 out of 100 people who take liraglutide. They are severe in less than 1 out of 100 people. In studies, about 11 out of 100 people stopped using liraglutide due to side effects.

Liraglutide also reduces blood sugar levels, so it can increase the risk of hypoglycemia (low blood sugar) in people who take diabetes medication. Because of this, it’s important to adjust the dose of diabetes medications accordingly. Liraglutide is not suitable for people over the age of 75, for example, or for people with certain kidney, liver, or gastrointestinal (stomach and bowel) diseases.

What about diet trends and wonder diets?

Many diet plans are advertised with over-the-top success stories, and some are extreme or one-sided. These diets can have side effects and come with medical risks like malnutrition. Also, the weight loss success can't be kept up in the long term. Dietary supplements haven't been scientifically proven to work here, either. As a result, medical societies advise people to avoid these diets.

The following three diet trends haven't been scientifically proven to work, either:

  • Diets with a low glycemic index (GLYX): The glycemic index ranks carbohydrate-rich foods according to how much they affect your blood sugar levels. The higher the glycemic index, the more (and faster) the blood sugar level rises. For example, bananas have a higher index than apples do. There is no clear scientific that eating foods with a low glycemic index has an effect on weight (in people who don't have diabetes) – or on other important health risk factors, for instance for heart disease. In people who have diabetes, though, these diets can lead to slightly better regulation of blood sugar levels.
  • Paleo diet: The paleo diet is supposed to consist of foods that people ate during the Stone Age. In practice, this means eliminating cereals, legumes, dairy products, and industrially produced foods like vegetable oils. Some people claim that this diet is particularly healthy because it’s the “original” human diet. But there's no scientific proof that this is true.
  • Intermittent fasting: In this diet, you don’t eat any food or drink any calorie-containing drinks for a certain time period each day. Different versions of the diet use different fasting periods. One possibility is to skip breakfast – for example, to eat dinner at 8 p.m. and then start eating again at 12 noon the next day. In the eight hours between noon and dinner, you don’t have to follow any specific rules. There is little research on interval fasting. It is especially unclear how successful this method is in the long term, or whether it works better than other weight loss approaches. But there's generally no reason to not try intermittent fasting.

Some diet trends are based on assumptions that have no scientific basis. And it’s also difficult to stick with one-sided or very restrictive diets in the long term.

What can you do to keep weight off in the long term?

Many diets are unsuccessful in the long term or even result in a yo-yo effect. This is where you put on weight again and end up weighing more than you did before the diet. To keep weight off in the long term, you have to make long-term changes too. Your diet has to be practical in daily life over the long term and still allow you to enjoy food.

With any diet, it’s important to not have unrealistic expectations or be disappointed and give up if you put on a little weight again. If you stick with it, you can keep off at least some of the weight you lost. Weighing yourself regularly (for example, on a particular day of the week) can help. Some people also like to use a body fat scale. These special scales allow you to see if you have gained muscle mass and lost fat, for example, even if your weight hasn't changed much. Things like better blood pressure or cholesterol readings can be a motivator too.

A number of studies have looked into what helps to keep weight off in the long term. You are most likely to succeed if you eat a diet that suits your body's energy needs and also get enough exercise. In other words, if you manage to not take in more calories than necessary and to exercise as well, you have good chances of keeping off the weight.

It is not easy to know when your daily energy needs have been met. In everyday life, it can help to

  • avoid big serving sizes,
  • use small plates,
  • eat only small amounts of fatty foods like sausage, cheese, fast food, cake, cookies, chocolate and potato chips (crisps),
  • drink only moderate amounts of high-calorie drinks like fruit juice, cola and iced tea, or replace them with low-sugar alternatives like diet drinks or fruit juice mixed with sparkling water, and
  • drink only small amounts of alcohol.

In general, it helps to take a look at the nutrition label on food packaging. This can help you get a sense of how many calories there are in different foods. Diaries or apps can help you keep track too.

Some people worry that sweeteners cause food cravings because they raise insulin levels for a short time. But scientific studies haven't found a link between sweeteners and body weight.

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IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. informedhealth.org can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

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Created on November 22, 2022

Next planned update: 2025


Institute for Quality and Efficiency in Health Care (IQWiG, Germany)

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