Management of type 2 diabetes: A handbook for general practice

Lifestyle interventions for management of type 2 diabetes


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Last revised: 17 Sep 2020

Grade: A, level 1A

In people with overweight or obesity with diabetes, a nutritionally balanced, calorie-reduced diet should be followed to achieve and maintain a lower, healthier body weight

Grade: A, level 1A

An intensive healthy behaviour intervention program, combining dietary modification and increased physical activity, may be used to achieve weight loss, improve glycaemic control and reduce CVD risk

Grade: A, level 1A

Weight management medication may be considered in people with diabetes and overweight or obesity to promote weight loss and improved glycaemic control

Grade: Consensus

Metabolic surgery should be recommended to manage type 2 diabetes:

  • in people with a body mass index (BMI) ≥40 kg/m2
  • in people with a BMI 35.0–39.9 kg/m2 when hyperglycaemia is inadequately controlled by lifestyle and optimal medical therapy

Grade: Consensus

Metabolic surgery should also be considered for patients with type 2 diabetes and BMI 30.0–34.9 kg/m2 if hyperglycaemia is inadequately controlled despite optimal treatment with either oral or injectable medications

These recommendations are drawn from the most recent recommendations from organisations including the National Health and Medical Research Council (NHMRC), the Scottish Intercollegiate Guidelines Network (SIGN), Diabetes Canada, the American Diabetes Association (ADA) and other relevant sources. Refer to ‘Explanation and source of recommendations’ for explanations of the levels and grades of evidence.

For people with type 2 diabetes who are overweight or obese, even modest weight loss (5–10%) may provide clinical benefits, including improved glycaemic control, blood pressure and lipid profiles, especially early in the disease process.20–22 Lifestyle-induced sustained weight loss contributes to the prevention, or delays progression, of diabetes.23–25

The relationship between weight loss and clinical benefits is complex, however. The multi-centre, randomised clinical trial Action for Health in Diabetes (Look AHEAD) provided evidence that intensive lifestyle intervention focusing on weight loss did not result in a significant reduction in cardiovascular eventsCl in overweight or obese adults with established type 2 diabetes.26 This was despite greater reductions in HbA1c and greater initial improvement in fitness and all CVD risk factors, except for low-density lipoprotein cholesterol levels. Increasing physical activity, regardless of weight loss, may reduce CVD risk factors,27 and reduce HbA1c by ~0.6% in adults with type 2 diabetes.28

The causes of overweight and obesity are likewise complex. Diet and physical activity are central to the energy balance equation, but are directly and indirectly influenced by a wide range of social, environmental, behavioural, genetic and physiological factors, the relationships between which are not yet fully understood. Older people with diabetes may also be at risk of malnutrition.

When managing patients, be mindful that some medications are associated with weight gain, including29 insulin, sulfonylureas, thiazolidinediones, second-generation antipsychotics (especially olanzapine and clozapine), beta-adrenergic blockers (especially propranolol), tricyclic antidepressants, lithium, pizotifen, sodium valproate and glucocorticosteroids.

Practice Point: The concept of diabetes remission

Diabetes ‘remission’ or even ‘reversal’ is often stated as one of the measured outcomes of clinical trials of weight loss interventions, usually defined as reduction or cessation of the use of glucose-lowering agents by participants.

However, the period that normalisation of glycaemia is sustained for varies in the long term, according to study length, intervention methods and time to follow-up. Thus, there is not high-quality evidence to support the concept of ‘reversal’ of diabetes from current interventions.

It is important to encourage a degree of healthy weight loss in anyone with type 2 diabetes who is overweight, except where there are other associated risks (eg in the frail and elderly, or those with eating disorders). Because a healthy body weight is sometimes not achievable, setting this as a goal might discourage patients from attempting any dietary change.

The Australian Obesity Management Algorithm is a practical clinical tool to guide the implementation of existing guidelines for the treatment of obesity in the primary care setting in Australia.

Weight assessment

Assessing weight is typically done using BMI, which can be a difficult parameter to standardise between different population groups.

For those of European descent, a healthy BMI is 18.5–24.9 kg/m2, overweight is 25–29.9 kg/m2 and obese is ≥30 kg/m2.6 Different classification criteria may apply to other population groups. Some groups may have equivalent levels of risk of health problems at a lower BMI (eg these BMI thresholds should be reduced by 2.5 kg/m2 for patients of Asian ethnicity7) or higher BMI (eg Torres Strait Islander and Maori peoples).30

It is advisable to also assess waist circumference (in centimetres), as this is a good indicator of total body fat and a useful predictor of visceral fat. Waist circumference of ≥94 cm in men and ≥80 cm in women conveys increased risk of obesity-related complications; ≥102 cm in men and ≥88 cm in women convey high risk.31 As with BMI, these values may differ for other population groups.6

Measuring waist circumference in patients with a BMI >35 kg/m2 may not add any further to predictive disease risk classification.32

Lifestyle interventions for weight management

In overweight or obese people with diabetes, a nutritionally balanced, energy-reduced diet should be recommended if a lower, healthier body weight is to be achieved and maintained as part of a multi-component lifestyle intervention (including healthy eating, physical activity and support for behavioural change).

Very low energy diets (VLEDs) can be considered as an initial weight loss strategy, when supervised lifestyle interventions have been unsuccessful in reducing weight, or when rapid weight loss is required (eg prior to bariatric or general surgery that is conditional on weight loss).33 These diets may be considered in adults with diabetes with BMI >27 kg/m2, taking into account each individual situation.34 A primary care–based weight loss study, the Diabetes Remission Clinical Trial (DiRECT), showed that VLED with associated weight loss led to 46% of participants reducing or ceasing diabetes medications after 12 months of intervention.35

VLEDs require regular appointments with appropriate health professionals to support the progress of the individual. Caution should be exercised if hypoglycaemia is a risk (people taking sulfonylureas and insulin). Use of sodium glucose co-transporter 2 (SGLT2) inhibitors in people on VLEDs or any high-protein, low-carbohydrate diet is not recommended (due to raised risk of ketoacidosis, which might be euglycaemic).


Pharmacotherapy is licensed by the Therapeutic Goods Administration (TGA) for weight management, including for patients with diabetes, but is not currently reimbursed by the Pharmaceutical Benefits Scheme (PBS). There are now four drugs that can be used as adjuncts to dietary changes and physical activity improvement: phentermine (a sympathomimetic amine), orlistat (an inhibitor of intestinal lipase), liraglutide (a glucagon-like peptide-1 receptor agonist [GLP-1 RA]) and combined naltrexone and bupropion.

These drugs may be considered in adults with diabetes with BMI ≥27 kg/m2, taking into account each individual situation.33

Each drug has the potential for significant clinical side effects and contraindications associated with its use. They require careful clinical risk–benefit assessment when applied in practice. Refer to the TGA website for more information.

Surgical interventions

Surgery for weight loss, also called metabolic or bariatric surgery, may induce weight loss in people who have failed by other means. The following procedures are used in Australia.7,34

  • Sleeve gastrectomy involves removing the greater portion of the fundus and body of the stomach, reducing its volume from up to 2.5 L to about 200 mL. This procedure provides fixed restriction and does not require adjustment like laparoscopic adjustable gastric banding (LAGB).
  • Roux-en-Y gastric bypass is a combination procedure in which a small stomach pouch is created to restrict food intake and the lower stomach, duodenum and first portion of the jejunum are bypassed to produce modest malabsorption of nutrients and thereby reduce kilojoule intake.
  • Biliopancreatic diversion is also a combination procedure that involves removing the lower part of the stomach and bypassing the duodenum and jejunum to produce significant malabsorption. This procedure tends to be performed in subspecialty centres.

Used in the past, LAGB is less used now in Australia and North America due to less sustained weight loss, fewer metabolic benefits and high surgical complication rates. This procedure involves placing a band around the stomach near its upper end to create a small pouch.6

Sleeve gastrectomy, Roux-en-Y gastric bypass and biliopancreatic diversion lead to sustained weight loss and normalisation (refer to ‘Practice Point’ above) of type 2 diabetes metabolic markers, although techniques vary in efficacy.6

The improvement in diabetes metabolic markers for Roux-en Y gastric bypass surgery at two-year follow-up was 52.7% in one meta-analysis, compared with 0.7% for medical management.36 For individuals who achieve improvement in diabetes metabolic markers with Roux-en-Y gastric bypass, the median period of sustained improvement is 8.3 years.7

Metabolic surgery in patients with type 2 diabetes is associated in non-randomised studies with reduction in microvascular and macrovascular complications as well as reduced mortality.7 Moreover, studies have also shown that metabolic surgery can prevent or delay the onset of type 2 diabetes in people with obesity.7

Taking into account each individual situation, metabolic surgery may be considered for people with a BMI >30 kg/m2 who have suboptimal BGLs, are at increased CVD risk and are not achieving recommended targets with medical therapy.7

GPs should assess the appropriateness of metabolic surgery for each individual patient and provide information on the risks, benefits and appropriateness of the type of procedure. Metabolic surgery performed in a high-volume specialist centre with an experienced surgical team may offer the lowest risks, and GPs should liaise with a specialised surgical team if there are concerns.33,34

Metabolic surgery, when indicated, should be included as part of an overall clinical pathway for adult weight management that is delivered by a multidisciplinary team (including surgeons, APDs, nurses, psychologists and physicians), and includes planning for surgery and continuing follow-up.33

Adverse events of metabolic surgery, particularly in the long term, need more research;37 however, suggested follow-up care includes monitoring for nutritional deficiencies and acid reflux disorders.38

Women of reproductive age who have had metabolic surgery need particular advice on contraceptive choices; those who plan to have a pregnancy need assessment, before and throughout pregnancy, regarding nutritional status, need for higher multivitamin dosages and close obstetric monitoring. Referral prior to pregnancy to appropriate specialty services is strongly advised, even if the diabetes appears well managed.

  1. National Institute for Clinical Excellence. Guidance for the use of patient-education models for diabetes. Technology appraisal guidance TA60. London: NICE, 2003.
  2. Nordmann AJ, Suter-Zimmermann K, Bucher HC, et al. Meta-analysis comparing Mediterranean to low-fat diets for modification of cardiovascular risk factors. Am J Med 2011;124(9):841–51.e2.
  3. American Diabetes Association. Standards of medical care in diabetes. Diabetes Care 2019;42:S1–194.
  4. Hordern MD, Dunstan DW, Prins JB, Baker MK, Singh MA, Coombes JS. Exercise prescription for patients with type 2 diabetes and pre-diabetes: A position statement from Exercise and Sport Science Australia. J Sci Med Sport 2012;15(1):25–31.
  5. National Health and Medical Research Council. Australian dietary guidelines. Canberra: NHMRC, 2013.
  6. Diabetes Canada Clinical Practice Guidelines Expert Committee. Diabetes Canada 2018 clinical practice guidelines for the prevention and management of diabetes in Canada. Can J Diabetes 2018;42:S1–325.
  7. Rubino F, Nathan DM, Eckel RH, et al. Metabolic surgery in the treatment algorithm for type 2 diabetes: A joint statement by international diabetes organizations. Diabetes Care 2016;39(6):861–77.
  8. The Royal Australian College of General Practitioners. Supporting smoking cessation: A guide for health professionals. 2nd edn. East Melbourne, Vic: RACGP, 2019.
  9. Scottish Intercollegiate Guidelines Network. Management of diabetes: A national clinical guideline (updated 2017). Edinburgh: SIGN, 2017.
  10. Colberg SR, Sigal RJ, Yardley JE, et al. Physical activity/exercise and diabetes: A position statement of the American Diabetes Association. Diabetes Care 2016;39(11):2065–79.
  11. Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. J Am Coll Cardiol 2001;37:153–46.
  12. Gellish RL, Goslin BR, Olson RE, McDonald A, Russi GD, Moudgil VK. Longitudinal modeling of the relationship between age and maximal heart rate. Med Sci Sports Exerc 2007;39(5):822–29.
  13. Yang Z, Scott CA, Mao C, Tang J, Farmer AJ. Resistance exercise versus aerobic exercise for type 2 diabetes: A systematic review and meta-analysis. Sports Med 2014;44(4):487–99.
  14. Church T, Blair S, Cocreham S, et al. Effects of aerobic and resistance training on hemoglobin a1c levels in patients with type 2 diabetes: A randomized controlled trial. JAMA 2010;304(20):2253–62.
  15. Dijk J, Manders R, Tummers K, et al. Both resistance- and endurance-type exercise reduce the prevalence of hyperglycaemia in individuals with impaired glucose tolerance and in insulin-treated and non-insulin-treated type 2 diabetic patients. Diabetologia 2012;55(5):1273–82.
  16. Briffa T, Maiorana A, Sheerin NJ. Physical activity for people with cardiovascular disease: Recommendations of the National Heart Foundation of Australia. Med J Aust 2006;184(2):71–75.
  17. Royal Australian College of General Practitioners. Exercise: Type 2 diabetes. In: Handbook of non-drug interventions (HANDI). East Melbourne, Vic: RACGP, 2014.
  18. Zaharieva D, Riddell M. Prevention of exercise-associated dysglycaemia: A case study-based approach. Diabetes Spectr 2015;28:55–62.
  19. Shukla AP, Iliescu RG, Thomas CE, Aronne LJ. Food order has a significant impact on postprandial glucose and insulin levels. Diabetes Care 2015;38(7):e98–99.
  20. Evert AB, Boucher JL, Cypress M, et al. Nutrition therapy recommendations for the management of adults with diabetes. Diabetes Care 2014;37(Suppl 1):S120–43.
  21. Anderson JW, Kendall CW, Jenkins DJ. Importance of weight management in type 2 diabetes: Review with meta-analysis of clinical studies. J Am Coll Nutr 2003;22:331–39.
  22. Bazzano LA, Serdula M, Liu S. Prevention of type 2 diabetes by diet and lifestyle modification. J Am Coll Nutr 2005;24:310–19.
  23. Knowler WC, Barrett-Connor E, Fowler SE, et al. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med 2002;346(6):393–403.
  24. Tuomilehto J, Lindstrom J, Eriksson JG, et al. Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance. N Engl J Med 2001;344(18):1343–50.
  25. Diabetes Prevention Program Research Group; Knowler W, Fowler S, Hamman R, et al. 10-year follow-up of diabetes incidence and weight loss in the Diabetes Prevention Program Outcomes Study. Lancet 2009;374(9702):1677–86.
  26. Look AHEAD Research Group; Wing RR, Bolin P, Brancati FL, et al. Cardiovascular effects of intensive lifestyle intervention in type 2 diabetes. N Engl J Med 2013;369(2):145–54.
  27. Shaw K, Gennat H, O’Rourke P, Del Mar C. Exercise for overweight or obesity. Cochrane Database of Systematic Reviews 2006;(4):CD003817. doi: 10.1002/14651858.CD003817.pub3.
  28. Thomas D, Elliott EJ, Naughton GA. Exercise for type 2 diabetes mellitus. Cochrane Database of Systematic Reviews 2006;(3): CD002968. doi: 10.1002/14651858.CD002968.pub2.
  29. Malone M. Medications associated with weight gain. Ann Pharmacother 2005;39:2046–55.
  30. Rush E, Plank L, Chandu V, et al. Body size, body composition, and fat distribution: A comparison of young New Zealand men of European, Pacific Island, and Asian Indian ethnicities. N Z Med J 2004;117(1207):U1203.
  31. Royal Australian College of General Practitioners. Guidelines for preventive activities in general practice. 9th edn. East Melbourne, Vic: RACGP, 2016.
  32. National Heart Lung and Blood Institute. The practical guide: Identification, evaluation and treatment of overweight and obesity in adults. Bethesda, MD: National Institutes of Health, 2000.
  33. Australian Obesity Management Algorithm working group. Australian Obesity Management Algorithm. Australia and New Zealand: Australian Diabetes Society, Australian and New Zealand Obesity Society, Obesity Surgery Society of Australian and New Zealand, 2016.
  34. National Health and Medical Research Council. Clinical practice guidelines for the management of overweight and obesity in adults, adolescents and children in Australia. Melbourne: NHMRC, 2013.
  35. Lean MEJ, Leslie WS, Barnes AC, et al. Primary care-led weight management for remission of type 2 diabetes (DiRECT): An open-label, cluster-randomised trial. Lancet 2018;391(10120):541–51.
  36. Khorgami Z, Shoar S, Saber AA, Howard CA, Danaei G, Sclabas GM. Outcomes of bariatric surgery versus medical management for type 2 diabetes mellitus: A meta-analysis of randomized controlled trials. Obes Surg 2019;29(3):964–74.
  37. Colquitt JL, Pickett K, Loveman E, Frampton GK. Surgery for weight loss in adults. Cochrane Database System Rev 2014;(8):CD003641. doi: 10.1002/14651858.CD003641.pub4.
  38. Via M, Mechanick J. Nutritional and micronutrient care of bariatric surgery patients: Current evidence update. Curr Obes Rep 2017;6:286–96.
  39. US Department of Health and Human Services. How tobacco smoke causes disease: The biology and behavioral basis for smoking-attributable disease: A report of the Surgeon General. Atlanta, GA: US Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2010.
  40. Targher G, Alberiche M, Zenere MB, Bonadonna RC, Juggeo M, Bonara E. Cigarette smoking and insulin resistance in patients with noninsulin-dependent diabetes mellitus. J Clin Endocrinol Metab 1997;82(11):3619–24.
  41. Pietraszek A, Gregersen S, Hermansen K. Alcohol and type 2 diabetes: A review. Nutr Metab Cardiovasc Dis 2010;20:366–75.
  42. National Health and Medical Research Council. Australian guidelines to reduce health risks from alcohol Canberra: NHMRC, 2020. [in publication].
  43. Cheyne EH, Sherwin RS, Lunt MJ, Cavan DA, Thomas PW, Kerr D. Influence of alcohol on cognitive performance during mild hypoglycaemia; implications for Type 1 diabetes. Diabet Med 2004;21(3):230–37.
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