Overweight and obesity (causes, environment and prescription)

Overweight and obesity are terms used to describe ranges of weight that have been shown to increase a person’s risk of certain conditions and health problems.

Body Mass Index (BMI) is a useful measure of overweight and obesity for adults. It is calculated from a person’s height and weight.

BMI	Classification
Below 18.5	Underweight
18.5 – 24.9	Healthy weight range
25.0 – 29.9	Overweight
30 and above	Obese

While BMI provides a good estimate of body fat for most people, it may not be suitable for some groups such as athletes who have a muscular build, older people and some ethnic groups.

Waist circumference is another good indicator of total body fat and can be a better predictor of health risk than BMI.

For tips on how calculate your BMI and measure your waist circumference, see assessing your weight.

Impact on health

Being overweight or obese can increase the risk of physical and mental health problems such as:

• heart disease
• high blood pressure
• high cholesterol
• stroke
• type 2 diabetes
• cancer
• joint problems such as gout, arthritis and joint pain
• gall bladder disease
• sleep problems
• reproductive problems
• low self-esteem and depression
• negative body image issues
• eating disorders
• social isolation and discrimination

Causes of overweight and obesity

The main cause of overweight and obesity is energy imbalance. Over time, if people eat and drink more than the body needs and uses in day-to-day activities, this extra energy will be stored as fat.

Many factors have contributed to the increasing rates of overweight and obesity, including:

• Food choices – choosing foods that are high in fat, sugar and/or salt that provide little nutrition and more energy than the body needs (such as cakes, biscuits, confectionary, chocolate, pastries, pies, potato chips, soft drinks, cordials, sports and energy drinks and alcoholic drinks).
• An inactive lifestyle – many Western Australians are not physically active enough for good health and spend too much time sitting.
• Genes – genetic factors may increase a person’s risk of being overweight or obese. Though genes alone do not explain the increase in population rates of overweight and obesity.
• The (obesity promoting) environment – the modern environment is one that makes it harder for people to be active enough and make healthy food choices:
  • Changes to the food supply have led to increased availability and promotion of cheap, processed foods which are high in energy and low in nutrients.
  • The portion size of many packaged foods and foods prepared outside the home has increased. The cost of these foods has also decreased when compared to healthier options.
  • More people now have desk jobs where they sit for most of the day.
  • Where people would once walk or cycle to get to places, many now travel by car.
  • More convenient lifestyles and devices like elevators and remote controls mean we use less energy.
  • Sedentary entertainment and recreation options such as watching the television and using the computer and other electronic devices rather than getting out and being active.
• Early life experiences – poor nutrition, smoking and gaining more than the recommended levels of weight during pregnancy can increase a child’s risk of becoming obese later in life. Evidence also shows that breastfeeding for at least six months reduces the risk of obesity in childhood, adolescence and early adulthood.

• Prescription weight-loss medication

  Losing weight requires a healthy diet and regular exercise. But in certain situations, prescription weight-loss medication may help.
  Keep in mind, though, that weight-loss medication is meant to be used along with diet, exercise and behavior changes, not instead of them. If you don't make these other changes in your life, medication is unlikely to work.
  Your doctor may recommend weight-loss medication if other methods of weight loss haven't worked for you and you meet one of the following criteria:
  • Your body mass index (BMI) is 30 or greater
  • Your BMI is greater than 27, and you also have medical complications of obesity, such as diabetes, high blood pressure or sleep apnea
  Before selecting a medication for you, your doctor will consider your health history, as well as possible side effects. Some weight-loss medications can't be used by women who are pregnant, or people who take certain medications or have chronic health conditions.
  Commonly prescribed weight-loss medications include orlistat (Xenical), lorcaserin (Belviq), phentermine and topiramate (Qsymia), buproprion and naltrexone (Contrave), and liraglutide (Saxenda).
  You will need close medical monitoring while taking a prescription weight-loss medication. Also, keep in mind that a weight-loss medication may not work for everyone, and the effects may wane over time. When you stop taking a weight-loss medication, you may regain much or all of the weight you lost.

  Weight-loss surgery

  In some cases, weight-loss surgery, also called bariatric surgery, is an option. Weight-loss surgery limits the amount of food you're able to comfortably eat or decreases the absorption of food and calories or both. While weight-loss surgery offers the best chance of losing the most weight, it can pose serious risks.
  Weight-loss surgery for obesity may be considered if you have tried other methods to lose weight that haven't worked and:
  • You have extreme obesity (BMI of 40 or higher)
  • Your BMI is 35 to 39.9, and you also have a serious weight-related health problem, such as diabetes or high blood pressure
  • You're committed to making the lifestyle changes that are necessary for surgery to work
  It doesn't guarantee that you'll lose all of your excess weight or that you'll keep it off long term. Weight-loss success after surgery depends on your commitment to making lifelong changes in your eating and exercise habits.
  It doesn't guarantee that you'll lose all of your excess weight or that you'll keep it off long term. Weight-loss success after surgery depends on your commitment to making lifelong changes in your eating and exercise habits.
  Common weight-loss surgeries include:
  • Gastric bypass surgery. In gastric bypass (Roux-en-Y gastric bypass), the surgeon creates a small pouch at the top of your stomach. The small intestine is then cut a short distance below the main stomach and connected to the new pouch. Food and liquid flow directly from the pouch into this part of the intestine, bypassing most of your stomach.
  • Laparoscopic adjustable gastric banding (LAGB). In this procedure, your stomach is separated into two pouches with an inflatable band. Pulling the band tight, like a belt, the surgeon creates a tiny channel between the two pouches. The band keeps the opening from expanding and is generally designed to stay in place permanently.
  • Biliopancreatic diversion with duodenal switch. This procedure begins with the surgeon removing a large part of the stomach. The surgeon leaves the valve that releases food to the small intestine and the first part of the small intestine (duodenum). Then the surgeon closes off the middle section of the intestine and attaches the last part directly to the duodenum. The separated section of the intestine is reattached to the end of the intestine to allow bile and digestive juices to flow into this part of the intestine.
  • Gastric sleeve. In this procedure, part of the stomach is removed, creating a smaller reservoir for food. It's a less complicated surgery than gastric bypass or biliopancreatic diversion with duodenal switch.

  Other treatments

  Vagal nerve blockade is another treatment for obesity. It involves implanting a device under the skin of the abdomen that sends intermittent electrical pulses to the abdominal vagus nerve, which tells the brain when the stomach feels empty or full. This new technology received FDA approval in 2014 for use by adults who have not been able to lose weight with a weight-loss program and who have a BMI of 35 to 45 with at least one obesity-related condition, such as type 2 diabetes.

  Preventing weight regain after obesity treatment

  Unfortunately, it's common to regain weight no matter what obesity treatment methods you try. If you take weight-loss medications, you'll probably regain weight when you stop taking them. You might even regain weight after weight-loss surgery if you continue to overeat or overindulge in high-calorie foods. But that doesn't mean your weight-loss efforts are futile.
  One of the best ways to prevent regaining the weight you've lost is to get regular physical activity. Aim for 60 minutes a day.
  Keep track of your physical activity if it helps you stay motivated and on course. As you lose weight and gain better health, talk to your doctor about what additional activities you might be able to do and, if appropriate, how to give your activity and exercise a boost.
  You may always have to remain vigilant about your weight. Combining a healthier diet and more activity in a practical and sustainable manner are the best ways to keep the weight you lost off for the long term.
  Take your weight loss and weight maintenance one day at a time and surround yourself with supportive resources to help ensure your success. Find a healthier way of living that you can stick with for the long term.