Comparing effects of a low-energy diet and a high-protein low-fat diet on sexual and endothelial function, urinary tract symptoms, and inflammation in obese diabetic men

J Sex Med. 2011 Oct;8(10):2868-75. doi: 10.1111/j.1743-6109.2011.02417.x. Epub 2011 Aug 5.


Introduction: Abdominal obesity and type 2 diabetes mellitus are associated with sexual and endothelial dysfunction, lower urinary tract symptoms (LUTS), and chronic systemic inflammation.

Aim: To determine the effects of diet-induced weight loss and maintenance on sexual and endothelial function, LUTS, and inflammatory markers in obese diabetic men.

Main outcome measures: Weight, waist circumference (WC), International Index of Erectile Function (IIEF-5) score, Sexual Desire Inventory (SDI) score, International Prostate Symptom Scale (IPSS) score, plasma fasting glucose and lipids, testosterone, sex hormone binding globulin (SHBG), inflammatory markers (high-sensitivity C-reactive protein [CRP] and interleukin-6 [IL-6]) and soluble E-selectin, and brachial artery flow-mediated dilatation (FMD) were measured at baseline, 8 weeks, and 52 weeks.

Methods: Over 8 weeks, 31 abdominally obese (body mass index ≥ 30 kg/m(2) , WC ≥ 102 cm), type 2 diabetic men (mean age 59.7 years) received either a meal replacement-based low-calorie diet (LCD) ∼1,000 kcal/day (N = 19) or low-fat, high-protein, reduced-carbohydrate (HP) diet (N = 12) prescribed to decrease intake by ∼600 kcal/day. Subjects continued on, or were switched to, the HP diet for another 44 weeks.

Results: At 8 weeks, weight and WC decreased by ∼10% and ∼5% with the LCD and HP diet, respectively. Both diets significantly improved plasma glucose, low-density lipoprotein (LDL), SHBG, IIEF-5, SDI and IPSS scores, and endothelial function (increased FMD, reduced soluble E-selectin). Erectile function, sexual desire, and urinary symptoms improved by a similar degree with both diets. CRP and IL-6 decreased with the HP diet. At 52 weeks, reductions in weight, WC, and CRP were maintained. IIEF-5, SDI, and IPSS scores improved further.

Conclusions: Diet-induced weight loss induces rapid improvement of sexual, urinary, and endothelial function in obese diabetic men. A high-protein, carbohydrate-reduced, low-fat diet also reduces systemic inflammation and sustains these beneficial effects to 1 year.

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blood Glucose / analysis
  • Body Mass Index
  • C-Reactive Protein / analysis
  • Caloric Restriction*
  • Diabetes Mellitus, Type 2 / drug therapy*
  • Diet, Fat-Restricted*
  • E-Selectin / blood
  • Humans
  • Inflammation / diet therapy*
  • Interleukin-6 / blood
  • Libido / physiology
  • Lipids / blood
  • Male
  • Middle Aged
  • Obesity / diet therapy*
  • Penile Erection* / physiology
  • Prostate / physiopathology
  • Sex Hormone-Binding Globulin / analysis
  • Testosterone / blood
  • Urologic Diseases / drug therapy*
  • Waist Circumference


  • Blood Glucose
  • E-Selectin
  • Interleukin-6
  • Lipids
  • Sex Hormone-Binding Globulin
  • Testosterone
  • C-Reactive Protein