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Lifestyle interventions for the management of overweight and obesity in adults

Last updated 20-07-2023

Multicomponent behavioural intervention remains the cornerstone of treatment for overweight and obesity. This page summarises the evidence for dietary interventions, physical activity and behaviour modification strategies.

Key Evidence

01

All dietary interventions to treat overweight and obesity work by reducing dietary energy intake to create an energy deficit

02

Individuals respond differently to various dietary interventions but level of adherence is key to success

03

Increase in structured exercise is required to control weight (together with dietary energy restriction) and is linked to health improvements

04

Regular weighing (once weekly) is a simple behavioural modification technique that has been proven to assist with weight management

This page has been written by the Boden Collaboration on Obesity, Nutrition, Exercise and Eating Disorders, University of Sydney; and reviewed by Professor Tim Gill.

The most effective way of limiting the health impact of overweight and obesity in the community is to prevent weight gain and limit the number of people developing these conditions. However, since more than two-thirds of the adult population in Australia is already overweight, significant efforts need to be directed at providing effective weight management services and interventions to people living with obesity.

Modest weight loss (5 to 10%) has been shown to have a profound effect on the risk of developing type 2 diabetes (T2DM) and is also associated with improvement in blood pressure, cardiovascular disease risk (CVD risk), joint pain, mobility, sexual dysfunction, depression and quality of life (see Healthy Weight Guide). Generally, more weight loss leads to greater improvement. Some conditions, such as sleep apnoea and non-alcoholic fatty liver disease may require 10–15% weight loss for a clinical improvement but for others, such as polycystic ovarian syndrome and fertility, there may be benefits with 2–5% weight loss.1 Achieving weight stability in people with an existing weight problem will help prevent deterioration in weight-related complications over time. For more details see Health benefits of weight loss.

It is clear that no single intervention will be efficacious, appropriate or acceptable for all people with obesity. Treatment should be individually tailored, and clinical care providers should be able to provide a spectrum of clinically proven treatment options in an individual or group setting.

Multicomponent behavioural intervention remains the cornerstone of overweight and obesity treatment and has been shown to result in significant weight loss with health benefits.2 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).

Dietary interventions

Numerous dietary approaches have been trialled to manage overweight and obesity but they all rely on reducing total energy intake. Researchers attempting to define the most effective overall dietary intervention have come to the conclusion that individuals will respond differently to each approach with the key defining feature of success being the level of adherence to each dietary approach.3 The use of a self-recorded food diary allows a qualitative assessment of the diet and can help to advise tailored dietary modifications.4

Energy deficit approach

All dietary interventions to treat overweight and obesity work by reducing the dietary energy intake to create an energy deficit. The simplest dietary approach for weight loss involves estimating the usual energy intake of an individual and recommending a healthy diet of at least 2500kJ (600kcals) less than one’s usual daily intake. This can be achieved through kilojoule (calorie) counting or following meal plans and is the basis of many commercial programs such as Weight Watchers, health applications and government initiatives such as the 8700 campaign.

Macronutrient composition

A number of dietary approaches to weight loss focus on altering the macronutrient content 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 body weight, 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.5 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.

Meal replacements

There are a number of commercial products (usually in the form of meals, bars and drinks) available in Australia containing a fixed energy content that can be used to replace one to two meals within the usual diet and thus create an energy deficit. The use of partial meal replacements has been associated with weight loss and improved overall diet quality.6 The convenience and flexibility of partial meal replacements may increase long term adherence, but transition back to normal foods will require appropriate support to ensure appropriate diet composition for weight loss maintenance and 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 in addition to assisting with weight control.7

Intermittent Energy Restriction

Intermittent Energy Restriction (IER), which involves significantly restricting energy intake on two to three days per week only (often known as the 5:2 diet), and Intermittent Fasting (IF), which involves avoiding food for whole days or for significant periods of the day, are forms of more intensive energy restriction.8 Some people find this eating pattern easier to adhere to and it is associated with comparable weight loss to more traditional diets9 but it is not recommended for children, the elderly and pregnant or lactating women.

VLEDs and other intense dietary programs

Very Low Energy Diets (VLEDs) are defined as hypocaloric diets which provide a maximum of 800kcals (3350kJ) per day and are usually provided in the form of shakes, soups or bars that are designed to contain the full complement of protein and micronutrients.10 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.11 VLED products replace normal foods and are usually prescribed for 12–16 weeks followed by gradual food reintroduction over 2–8 weeks but have been safely adhered to for up to 12 months.11 When used appropriately, VLEDs can achieve weight loss of around 1–2.5 kg a week12 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.11

Physical activity

Physical activity is an integral part of overweight and obesity management. Although very high levels of exercise (over 300 mins/week)13 are required to achieve reductions in body weight, positive changes in visceral and other ectopic fat stores, and improvements in cardiovascular health occur with relatively low levels of regular, moderate-intensity activity (150 mins/week or less).14 The addition of resistance exercise (three sessions/week) leads to improved outcomes and also increases muscle strength.4 Increases in structured exercise together with dietary energy restriction will be required to control weight but physical activity counselling should also include advice on habitual physical activity in everyday life. Exercise prescription must be tailored to the patient’s ability and health status and focus on a safe and gradual increase.15

Behaviour modification strategies

Strategies focusing on modifying behaviours that contributed to developing 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.16

Most behaviour modification strategies focus on:

  1. increasing awareness around triggers for problem behaviours
  2. identifying feelings and beliefs around weight issues
  3. increasing structure around common weight related behaviours
  4. providing support that enables change, and
  5. setting realistic goals for change.

Self-monitoring, by use of diet and activity applications or devices may be helpful. Regular weighing (once weekly) is a simple behavioural modification technique that has been proven to assist with weight management.17 Identifying and eliminating cues for problem behaviours within the home or work environment is also a useful strategy. Additional professional help may be required with other approaches such as cognitive behaviour therapies (CBT) which aim to help a patient modify both their insight and understanding of thoughts and beliefs concerning weight regulation, obesity and its consequences as well as addressing behaviours that require change for successful weight loss and weight loss maintenance.18

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 often include frequent weekly meetings 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 behavioural program delivered in primary care although this difference did not persist at a 24 month follow up.19

Importance of ongoing care and long-term follow up

Obesity is a 'chronic relapsing disease process' requiring follow-up and ongoing management to prevent weight regain, monitor disease risks and treat 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.

For information on medication and surgical treatment options for adults with obesity, see Medication and surgery for adults.

References

1. Ryan DH, Yockey SR. Weight Loss and Improvement in Comorbidity: Differences at 5%, 10%, 15%, and Over. Curr Obes Rep 2017; 6: 187–194
2. Curry SJ, Krist AH Owens DK et al for the US Preventive Services Task Force. Behavioral Weight Loss Interventions to Prevent Obesity-Related Morbidity and Mortality in Adults: US Preventive Services Task Force Recommendation Statement. JAMA. 2018 ;320(11):1163–71
3. Dansinger ML, Gleason JA, Griffith JL, Selker HP, Schaefer EJ. Comparison of the Atkins, Ornish, Weight Watchers, and Zone diets for weight loss and heart disease risk reduction: a randomized trial. JAMA 2005; 293: 43–53.
4. Yumuk V, Tsigos C, Fried M, Schindler K, Busetto L, Micic D, Toplak H, for the Obesity Management Task Force of the European Association for the Study of Obesity. European guidelines for obesity management in adults. Obes Facts. 2015; 8:402–24
5. Brouns F. Overweight and diabetes prevention: is a low-carbohydrate-high-fat diet recommendable?. Eur J Nutr. 2018; 57:1301–12.
6. Astbury NM, Piernas C, Hartmann-Boyce J, Lapworth S, Aveyard P, Jebb SA. A systematic review and meta-analysis of the effectiveness of meal replacements for weight loss. Obes Rev. 2019; 20(4):569–87.
7. Shai I, Schwarzfuchs D, Henkin Y, Shahar DR, Witkow S, Greenberg I, Golan R, Fraser D, Bolotin A, Vardi H, Tangi-Rozental O, Zuk-Ramot R, Sarusi B, Brickner D, Schwartz Z, Sheiner E, Marko R, Katorza E, Thiery J, Fiedler GM, Bluher M, Stumvoll M, Stampfer MJ, for the Dietary Intervention Randomized Controlled Trial (DIRECT) Group: Weight loss with a low-carbohydrate, Mediterranean, or low-fat diet. N Engl J Med 2008; 359:229–241.
8. Rynders CA Thomas EA, Zaman A, Pan Z, Catenacci VA7, Melanson EL. Effectiveness of Intermittent Fasting and Time-Restricted Feeding Compared to Continuous Energy Restriction for Weight Loss. Nutrients. 2019 Oct 14;11(10).
9. Cioffi I, Evangelista A, Ponzo V, Ciccone G, Soldati L, Santarpia L, Contaldo F, Pasanisi F, Ghigo E, Bo S. Intermittent versus continuous energy restriction on weight loss and cardiometabolic outcomes: a systematic review and meta-analysis of randomized controlled trials. J Transl Med. 2018 Dec 24;16(1):371.
10. Gibson AA, Franklin J, Pattinson AL, Cheng ZG, Samman S, Markovic TP & Sainsbury A. (2016). Comparison of Very Low Energy Diet Products Available in Australia and How to Tailor Them to Optimise Protein Content for Younger and Older Adult Men and Women. Healthcare (Basel, Switzerland), 4(3), 71. https://doi.org/10.3390/healthcare4030071
11. National Health and Medical Research Council. Clinical practice guidelines for the management of overweight and obesity in adults, adolescents and children in Australia. Melbourne 2013. Available from: https://www.nhmrc.gov.au/...
12. Mustajoki P, Pekkarinen T. Very low energy diets in the treatment of obesity. Obes Rev. 2001; 2(1):61–72.
13. SIGN (Scottish Intercollegiate Guidelines Network). Management of obesity. A national clinical guideline Edinburgh: SIGN; 2010 [115:[Available from: http://www.sign.ac.uk/guidelines/fulltext/115/index.html.
14. Keating SE, Johnson NA, Mielke GI, Coombes JS. A systematic review and meta‐analysis of interval training versus moderate‐intensity continuous training on body adiposity. Obesity Reviews. 2017;18(8):943–64.
15. Yumuk V, Fruhbeck G, Oppert JM, Woodward E, Toplak, for the Executive Committee of the European Association for the Study of Obesity. An EASO position statement on multidisciplinary obesity management in adults. Obes Facts. 2014; 7:96–101
16. Hartmann-Boyce J, Aveyard P, Piernas C, Koshiaris C, Velardo C, Salvi D, Jebb SA. Cognitive and behavioural strategies for weight management in overweight adults: Results from the Oxford Food and Activity Behaviours (OxFAB) cohort study. PLoS One. 2018 Aug 10;13(8):e0202072
17. Burke LE, Wang J, Sevick MA. Self monitoring in weight loss: a systematic review of the literature. J Am Diet Assoc. 2011; 111(1):92–102
18. Sharma M: Behavioral interventions for preventing and treating obesity in adults. Obes Rev 2006;7:183–200.
19. Holzapfel C, Cresswell L, Ahern AL, Fuller NR, Eberhard M, Stoll J, Mander AP, Jebb SA, Caterson ID, and Hauner H. The challenge of a 2-year follow-up after intervention for weight loss in primary care. Int J Obes 2014; 38(6): 806–11.