Family Medicine Residency Program, Mayo Clinic Florida, Jacksonville (Drs. McMullan and Kimsey); Jacksonville Family Medicine Residency Program, Uniformed Services University of Health Sciences, FL (Dr. Smith) mcmullan.stephen@mayo.edu
The authors reported no potential conflict of interest relevant to this article.
The views expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Department of the Navy, Department of Defense, or the United States government.
A review by Salas-Salvadó et al14 showed that a vegan diet yields an average A1C reduction of 0.41% (95% CI, –0.58 to –0.23).Several meta-analyses report similar effects on A1C with vegetarian and vegan eating patterns.6,15,16 The ADA review notes that weight loss was more significant in the vegan group and concluded that this diet should be studied further while controlling for weight loss.6
Mediterranean diet
The Mediterranean diet emphasizes vegetables, whole grains, fruits, lean meats, nuts, and olive oil. The benefits of the Mediterranean diet are well known and, as a result, the diet is recommended by organizations including the American Heart Association as part of a strategy to reduce cardiovascular risk (TABLE 17-10).
Mediterranean diet interventions have generally shown mixed effects on A1C reduction, weight management, and lipid control in type 2 diabetes.6 The PREDIMED trial is the largest and longest randomized controlled trial to date comparing the Mediterranean diet to a low-fat diet.17 This trial has reliably shown a reduced risk for type 2 diabetes and a trend to reduced A1C.17 A reduction in the need for glucose-lowering medications was demonstrated in a subgroup analysis of the intervention group (adjusted hazard ratio = 0.78; 95% CI, 0.62-0.98).18 Also, the Mediterranean diet has shown a significant reduction in the incidence of cardiovascular disease in patients with type 2 diabetes.6
Physical activity and exercise
What do current guidelines recommend?
For most adults with type 2 diabetes, current guidelines by the ADA and by the National Institute of Diabetes and Digestive and Kidney Diseases recommend at least 150 minutes of moderate-to-vigorous intensity exercise every week spread out over at least 3 days, with no more than 2 consecutive days without exercise; and resistance training at least 2 other days per week which should balance all major muscle groups (TABLE 219-21). The benefits of exercise for type 2 diabetes have been well reviewed: positive effects on glucose control, insulin sensitivity, cardiovascular disease, lipid profiles, skeletal muscle metabolism, and solid-organ functioning.19,22,23
Grace et al24 showed in a meta-analysis that moderate aerobic exercise reduced A1C by 0.69% (95% CI, –1.09 to –0.3) at 13 weeks, and a Cochrane review showed an average A1C reduction of 0.6% with moderate-intensity exercise.25 Borror et al26 demonstrated in a systematic review that postprandial moderate-intensity aerobic exercise starting 1 hour after meals results in a reduced 24-hour prevalence of hyperglycemia (33.5% reduction vs control). A meta-analysis in China showed an average A1C reduction of 0.68% for patients performing a Tai Chi physical activity intervention.27
Continue to: Consider high-intensity interval training
