Lifestyle interventions for the management of overweight and obesity in adults
Multicomponent lifestyle intervention remains the cornerstone of treatment for overweight and obesity. This page summarises the evidence for dietary and physical activity interventions, as well as other behaviour modification strategies.
Key Evidence
Dietary interventions to treat overweight and obesity work by reducing dietary energy intake to create an energy deficit
Dietary interventions should be tailored to the individual and take a person-centred approach that respects the individual’s circumstances, goals and decisions
Regular exercise is also necessary to support weight management (together with dietary interventions), , and is linked to additional improvements in physical and mental health
Appropriate support for lifestyle change is essential. For example, access to health professionals such as doctors, dietitians and exercise physiologists. Additionally, broader factors that limit lifestyle change should be acknowledged and addressed, such as access to affordable healthy food, infrastructure that supports physical activity
Lifestyle interventions focused on nutrition and physical activity are the foundation of obesity management and usually the first line of treatment.1234 However, lifestyle interventions alone may not be effective in meeting the clinical management goals and the individual’s goals due to the complex causes of obesity.1 Additional treatment options are available such as medication and surgery, information is available here. Most guidelines suggest progressively more intensive interventions may be required in those with greater obesity and/or in the presence of weight related complications (see The Australian Obesity Management Algorithm).
Government investment is required in effective weight management services and lifestyle modification interventions to appropriately support people living with overweight and obesity, as well as creating supportive environments for healthy eating and being physically active.
There are a range of health benefits from weight loss and healthy lifestyle changes, which are detailed here. Achieving weight stability in people who are experiencing weight gain will help prevent deterioration in weight-related complications over time. Maintaining lifestyle changes and weight loss long-term can be challenging and management approaches should reflect this by providing ongoing monitoring and support.15
It is clear that no single intervention for weight management will be efficacious, appropriate or acceptable for all people with obesity given the complex causes and individual differences.1 Evidenced based recommendations, including the draft of the updated Australian Clinical Practice Guidelines for the Management of Overweight and Obesity, advise healthcare professionals to develop a tailored treatment plan collaboratively with the person living with overweight or obesity.6 Treatment should be person-centred and individually tailored based on the individual’s goals, preferences, cultural background, weight history, health conditions, family history, eating disorder risk, psychosocial factors and prognosis.167 Clinical care providers should be able to provide a spectrum of clinically proven treatment options, delivered in an individual or group setting. It’s important before providing treatment for overweight and obesity that the presence of an eating disorder is considered, given the crossover in symptoms and high rates of eating disorders in people with higher weight.8 If an eating disorder is diagnosed, it’s recommended to prioritise eating disorder treatment in line with guidelines.9
Multicomponent lifestyle interventions remain the cornerstone of weight management and can result in significant weight loss with health benefits.10 Lifestyle interventions may include advice about improving nutrition, increasing physical activity, as well as decreasing sedentary behaviour, improving sleep hygiene and stress management.1 Interventions may also include psychological treatment and involving family members for support (particularly among children and adolescents living with obesity).6 Weight loss may not be an appropriate or acceptable treatment goal for some people with obesity. Instead, a weight-neutral approach can be used which focuses on health promoting behaviours to optimise health and wellbeing instead of aiming for weight loss.1112
Dietary interventions
Numerous dietary approaches have been trialled to manage overweight and obesity, including those described below. Most rely on reducing total energy intake for weight loss through approaches that vary the amount or type of food eaten or eating behaviours such as timing. Researchers attempting to define the most effective overall dietary intervention have concluded that individuals will respond differently to each approach, with the key defining feature of success being the level of adherence to each dietary approach as guided by the individual’s preferences.13 To support ongoing adherence, the use of a self-recorded food diary may be recommended, as it allows for an assessment of the diet to occur, and can help to advise tailored dietary modifications.14
Energy deficit approach
Dietary interventions to treat overweight and obesity through weight loss work by reducing the dietary energy intake to create an energy deficit. The simplest dietary approach for weight loss involves eating a healthy diet and reducing usual energy intake by approximately 2,000-3,100 kJ (500-750 kcal) per day.15 This can be achieved through kilojoule (kJ) (calorie) counting or following meal plans based on the Australian Dietary Guidelines16 and is the basis of many commercial programs, such as Weight Watchers and mobile phone health apps.
Macronutrient composition
A number of dietary approaches to weight loss focus on altering the macronutrient content (carbohydrate, fat, protein) of the diet but their efficacy is more from greater adherence, leading to reduced total energy intake. Ad libitum low carbohydrate and low fat diets have both been shown to reduce bodyweight, with a very low carbohydrate diet showing the best short term results in trials, possibly as a result of ketone production contributing to stronger appetite inhibition.1718 However, long-term weight loss is not affected by macronutrient content and the food groups recommended by the Australian Dietary Guidelines should still be followed for weight management and overall health.
Specific diet or meal patterns
Some weight control programs are based around adopting a recommended dietary pattern with no overt focus on energy intake. The most widely studied diet pattern is the “Mediterranean Diet”, which is based on a high intake of vegetable, legumes, nuts and fruit, moderate meat intake and replaces saturated fat with monounsaturated fats, such as olive oil. Research indicates that this style of eating has a number of metabolic benefits (such as reduced risk of cardiovascular disease) in addition to assisting with weight control.19 The Dietary Approaches to Stop Hypertension (DASH) diet is indicated to reduce blood pressure in the management and prevention of hypertension. Evidence shows that the DASH dietary pattern also supports weight loss.20
Intermittent fasting and time restricted eating
Intermittent fasting, also known as intermittent energy restriction is a dietary approach that alternates between periods of fasting with no or low food intake and periods of normal eating. There are a variety of intermittent fasting patterns that vary the periods of eating and fasting over the day or week. For example, the 5:2 diet includes a weekly split of 5 days of normal eating and 2 days of “fasting” with very low intake, such as 25% of energy needs.21 Time restricted eating involves a daily period of fasting without food intake, such as 12-21 hours, followed by eating normally for the remainder of the day.21 Unlike many dietary approaches, intermittent fasting or time restricted eating focuses more on when you eat rather than what you eat. Some people find this eating pattern easier to adhere to and it is associated with comparable weight loss and metabolic improvements to more traditional diets.212223 However, it is not recommended for children, the elderly, pregnant or lactating women and individuals at risk or with an eating disorder.24
Very Low Energy Diets (VLEDs) and Low Energy Diets (LEDs)
Very Low Energy Diets (VLEDs) provide a maximum of 3350kJ per day (800 kcal) and are usually provided in the form of nutritionally complete shakes, soups or bars plus some limited food such as vegetables.25 They may be appropriate where other dietary and physical activity strategies have been unsuccessful or when weight presents a significant health risk and/or rapid weight loss is required.4 VLEDs are an intensive diet and should be done under medical supervision such as a GP and dietitian. VLED use meal replacement products to replace normal foods and are prescribed for a limited time, usually between 8-16 weeks followed by gradual food reintroduction over 2-8 weeks.4 When used appropriately, VLEDs can achieve weight loss of around 1.5-2.5 kg a week26 but additional care and follow up using other interventions is required after this treatment to prevent weight regain or to enable continued weight loss. If tolerated, they can be an appealing option due to the reduced burden of food choice, ease of preparation and motivating effect of initial rapid weight loss. They are not suitable for all people (e.g. pregnant and lactating women and the elderly) and in rare cases may be associated with serious side effects, so must be supervised by an appropriately trained health professional.4 There’s evidence supporting the role of exercise, particularly resistance exercise, and ensuring adequate protein intake to preserve lean body mass during weight loss.2728
As the name suggests, Low Energy Diets (LEDs) are a similar, less intensive approach than VLED. The diet aims for a maximum of 3350-5000 kJ per day (800-1200kcal)29 which may be achieved through the replacement of some meals or snacks with commercial meal replacement products (e.g. shakes, meals, bars and soups) which contain a fixed energy content. The use of partial meal replacements has been associated with weight loss and improved overall diet quality.30 The convenience and flexibility of partial meal replacements may increase long term adherence, but the transition back to normal foods will require appropriate support to ensure appropriate diet composition for weight loss maintenance and health.30
Weight neutral approaches
By taking a patient centred approach to lifestyle interventions, it also enables dietary interventions that are less prescriptive and do not have a weight loss focus. Instead, these weight neutral approaches focus on overall health promoting behaviours including dietary behaviours and diet quality that are beneficial for health and wellbeing.1112 A systematic review described the following eating behaviours used in weight neutral approaches: intuitive eating, mindful eating, and eating competence.11 These approaches were associated with higher diet quality and physical activity.11 Whilst not the aim, these approaches may still lead to a reduction in weight.
Physical Activity and sedentary behaviour
Physical activity is an integral part of overweight and obesity management.313233 Although physical activity alone has a modest impact on weight loss, it has numerous health benefits.32 Resistance (strength) training preserves lean body mass during weight loss and increases muscular fitness.3233 Both aerobic and resistance exercise improves cardiorespiratory fitness and insulin sensititvity.32 Exercise improves body composition such as positive changes in visceral and other ectopic fat stores.323334
Regular aerobic and strengthening physical activity is recommended, along with reducing and breaking up sedentary behaviour of long periods of sitting and screen time (e.g. TV, video games, computers, mobile phones).6 Australia’s draft of the updated Clinical Practice Guidelines for the Management of Overweight and Obesity recommends adults are physically active at least 150 minutes per week and do muscle strengthening activities on at least two days a week, per the Australian Physical Activity Guidelines.635 The Australian Physical Activity Guidelines for adults are shown in the table below.
An individualised plan and gradual increase in physical activity is important for people with overweight and obesity who are inactive, particularly those older than 40 years or with weight-related complications including mobility limitations and chronic pain.635 Weight stigma and mental health may also be a barrier to participation in structured exercise. Appropriately trained professionals such as physiotherapists and exercise physiologists can support people to safely engage with physical activity. Exercise plans should be tailored to the individual’s ability, personal preferences and health status, with a focus on a safe and gradual increase to prevent injury and encourage adherence. Given the well documented physical and mental health benefits of regular exercise, an emphasis is on “any activity is better than none”.35
Table 1: Australian physical activity guidelines for adults aged 18-65 years
Australian Government Department of Health, Disability and Ageing
https://www.health.gov.au/resources/collections/collection-of-physical-activity-and-sedentary-behaviour-guidelines-for-all-ages
| - | Adults (18 to 65 years) |
|---|---|
| Physical activity | Be active on most (preferably all) days. |
| Weekly total of: 150 to 300 minutes (2.5 to 5 hours) of moderate activity or 75 to 150 minutes (1.25 to 2.5 hours) of vigorous activity or an equivalent combination of both. | |
| Strengthening activities | At least 2 days a week. |
| Sedentary time | Minimise and break up long periods of sitting. |
Other lifestyle factors and behaviour modification strategies
Sleep is an important factor to consider in weight management as insufficient sleep can lead to physiological changes and impact lifestyle behaviours.363738 Insufficient sleep (duration and quality) causes metabolic changes including changes in the hormones that regulate appetite.39 Sleep hygiene interventions aim to adjust sleep duration (often increase), improve sleep quality or adjust irregular sleep timing.
Strategies that focus on modifying behaviours that contribute to the development of overweight and obesity have been shown to be an effective treatment, and have more sustained outcomes when used either alone or in conjunction with other treatments.40 Most behaviour modification strategies focus on: (i) increasing awareness around triggers for unhelpful behaviours, (ii) identifying feelings and beliefs around weight issues, (iii) increasing structure around common weight related behaviours, (iv) providing support that enables change and (v) setting realistic goals for change.40 Self-monitoring, by use of diet and activity applications or devices may be helpful.41 Regular self-weighing (once weekly) is a simple behavioural modification technique that can assist with weight management.4142 However, self-weighing can have adverse effects and may not be appropriate for young adults or people at risk of eating disorders.43 Healthcare professionals should assess if regular self-weighing is suitable for an individual, monitor their response to ensure it is a positive and helpful tool and provide support as needed.42
Psychological support can be helpful to navigate lifestyle changes to nutrition and physical activity, address underlying psychological contributors to obesity, provide treatment for mental illness, support stress management and overall wellbeing.4445 An effective therapy approach is cognitive behaviour therapy (CBT), which aims to help a patient identify and modify thought patterns and beliefs that are unhelpful, to help change behaviour and how they feel.46
Commercial weight loss programs
Many commercial face-to-face or online weight loss programs exist in Australia, but only a few have been independently evaluated. Most of these programs aim to educate and motivate participants to lose weight by promoting a reduced energy intake with balanced eating, increased physical activity and group support. They may include regular meetings or virtual workshops that focus on intensive behavioural therapy and cognitive restructuring. Research has suggested that well developed and delivered programs can be effective in assisting weight loss. A large international trial of Weight Watchers produced a modest weight loss (≥ 2.5 kg) at 12 months that was significantly greater than the comparator of a physician led lifestyle program delivered in primary care although this difference did not persist at a 2 year follow up.47
Importance of ongoing care and long-term follow up
Obesity is a complex, chronic condition and people require long-term access to appropriate healthcare and support to address the multi-factorial causes, as well as monitoring of disease risks and treatment for weight-related complications.
Obesity management is multidisciplinary by nature and requires the ability to draw on professionals with complementary expertise. Delivering comprehensive treatment to those with obesity represents a major challenge for the Australian health care system and specialist obesity treatment services are required to support primary care. Broader changes to environmental influences, such as the actions of the food industry, are also needed to support healthy lifestyles. For more information: Environmental.
For information on medication and surgical treatment options for adults with obesity, see Medication and surgery for adults.
Content for this page was originally written by the Boden Institute, The University of Sydney. It was updated by Josephine Marshall at the at the Global Centre for Preventive Health and Nutrition at Deakin University and reviewed by Professor Tim Gill at the Obesity Collective. For more information about the approach to content on the site please see About | Obesity Evidence Hub.