Physician’s guide to weight loss therapy

• Cornerstone treatment of obesity: Lifestyle therapy modifications are the cornerstone of all weight loss therapy and should be the first-line intervention for all individuals. Importantly, lifestyle modifications must be included as part of any weight loss intervention.²  
  

• Body Mass Index (BMI) kg/m²: Lifestyle therapy modifications for weight loss are recommended for all individuals with a BMI ≥25 kg/m².
  

In various studies, lifestyle modifications, including low-calorie diets, have shown to reduce weight by between 3-8%.^6,7

Lifestyle changes encompass three main categories:

• Diet modification: Typically involving calorie reduction diets. Many diets exist, including low carbohydrate, low glycaemic index, low fat or Mediterranean diets.⁵
• Increased physical activity: Implementation of regular aerobic exercise and/or strength training.⁵ 
• Behavioural change: Targeting habit change, self-monitoring, and goal-setting. This may include cognitive-behavioural therapy for obesity to facilitate change in thinking patterns.⁵

Diet modification is based on calorie reduction from dietary sources and causes patients to lose body weight through a calorie deficit.⁵ As the body uses fat stores in the liver and fatty tissues as fuel, rather than food, this causes a reduction in weight.

Increased exercise also contributes to calorie deficit as calories are used for physical movement.⁵ Regular bouts of aerobic exercise can also reduce blood pressure and hyperlipidaemia which are obesity-related risks.⁵ However, physical activity alone has been shown to have limited benefit in weight loss without calorie restriction.⁵ Therefore, a combination approach is best.

Behavioural change therapy works by setting realistic goals and self-monitoring. Counter-intuitively, this is a holistic approach which recognises that multiple factors outside of behaviour contribute to obesity, such as genetics and hormonal influences. That’s why behavioural therapy aims to set specific goals within a range that an individual can realistically reach.⁵ Regular self-monitoring has consistently been linked to both short and long-term weight loss and this is incorporated into behavioural therapy.⁵  Crucially, through cognitive restructuring, psychological triggers can be modified so that patients can overcome unhealthy eating habits.⁵

• Lack of patient compliance: Weight loss through lifestyle modifications tends to be challenging for patients. A combination of psychological, physiological, and socioeconomic factors contribute to difficulty of sustained habit changes. Healthcare professionals may also find lifestyle modification difficult to initiate, with time constraints often cited as a key barrier.¹
• Rebound weight gain: Lifestyle interventions are not always sufficient to maintain weight loss.^{8, 9} In fact, studies show that in the long-term, weight loss is not sustained and there is instead weight gain compared to the initial weight.  Mann et al. (2007) completed a review of randomised control trials of patients on calorie-restricting diets. The results showed that, in the long term, between one to two-thirds of those on such a diet regained more weight than they originally lost on their diets.⁸

To learn more about diet difficulties, visit ‘Why don’t diets work?’. 

For more guidance on Lifestyle Therapy Modifications, see page 91 of the AACE/ACE Guidelines (2016).

• Management of severe excess weight: Bariatric surgery is the third-line and currently most efficient intervention for obesity management. It is intended to manage excess weight that is severe and/or associated with severe weight-related complications.^3,15 Its efficacy for severe excess weight makes it a suitable morbid obesity treatment. 
• BMI kg/m²: Bariatric surgery is used in patients with a BMI ≥40 kg/m², more than 45kg overweight or with a BMI ≥35 kg/m² and at least one or more obesity-related complication.^3,15

There are a number of different types of weight loss surgery, with each option providing different weight loss efficacies ranging between 7-38%.^16,17 This efficacy means that bariatric surgery can be a highly effective method of weight loss for patients who are overweight or living with obesity.

One study showed that rebound weight gain can occur in up to 50% of people, two years following surgery.¹⁸ The percentage of weight regain varied amongst individuals and depending on the type of bariatric surgery, studies have shown a mean weight regain of between 8-23.4% of the initial weight loss.^{18, 19} Although there can be rebound weight gain, overall weight loss through bariatric surgery remains high compared to non-surgical weight loss treatments.^3,15 This makes bariatric surgery an effective treatment for weight loss.

The most common types of weight loss surgery are:

• Gastric band: A band is placed around the stomach and this limits stomach distension. As a result, patients feel fuller much sooner.²⁰ 
• Roux-en-Y gastric bypass: The top of the stomach is attached to the start of the small intestine. This causes the stomach to fill more quickly, allowing patients to feel fuller, sooner.²⁰ 
• Sleeve gastrectomy: A part of the stomach is removed surgically so that the patient can feel full with decreased food intake.²⁰

Weight loss surgery can be invasive and there is a risk of postoperative complications.¹⁵ These risks vary depending on the surgery type.¹⁵ Typical surgical complications include bleeding, herniation, peritonitis, deep vein thrombosis and post-operative vitamin malabsorption among others.^15,21 Some of these complications can be more serious than others but overall, peri-operative mortality is low and occurs in less than 1%.²¹

For more guidance on Bariatric Surgery, see page 131 of the AACE/ACE Guidelines (2016). 

Below, you can also find a practical overview of the appropriate suggested obesity therapy, based on your diagnosis and complication-specific staging.