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Introductions

Introductions. Name Email address Favorite type of food Least favorite food Magazine you read most often All-time favorite movie Concert/performance you’d most want to see People would be surprised to learn this about me. Low Carbohydrate Diets and Weight Loss. David L. Gee, PhD

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Introductions

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  1. Introductions • Name • Email address • Favorite type of food • Least favorite food • Magazine you read most often • All-time favorite movie • Concert/performance you’d most want to see • People would be surprised to learn this about me.

  2. Low Carbohydrate Diets and Weight Loss David L. Gee, PhD FCSN 547 - Nutrition Update Summer 2004

  3. The Low-Carbohydrate Diet of William Banting • Age: 66 yrs • Weight Loss: • 46 pounds of initial 202 pounds • over one year • “Never hungry” • Letter on Corpulence, Addressed to the Public. 2nd ed., London, England, Harrison and Sons; 1863.

  4. Efficacy and Safety of Low-Carbohydrate Diets: A Systematic Review D. Bravata et al JAMA 2003;289:1837-1850

  5. Efficacy and Safety of Low-Carbohydrate Diets: A Systematic Review • MEDLINE search for low-carbohydrate diet studies from 1966-2003 • > 4 days, > 500 Cal/d, reported Cal & CHO content, relevant outcomes • 107 articles with 3268 participants • 663 participants consuming < 60gCHO/d • 71 participants consuming < 20gCHO/d • No low-carb diets with participants >53 yo • Only 5 studies (non-randomized, no comparison groups) with diet duration of > 90 days.

  6. Efficacy and Safety of Low-Carbohydrate Diets: A Systematic ReviewFindings: • Weight loss in obese subjects associated with: • longer diet duration (p=0.002) • restriction of calorie intake (p=0.03) • but not carbohydrate content (p=0.90) • Low-carbohydrate diets had no significant adverse effect on fasting serum lipids, glucose, insulin or blood pressure • Concluded: ‘insufficient evidence to make recommendations for or against the use of low-carbohydrate diets…’

  7. A Low-Carbohydrate, Ketogenic Diet Versus a Low-Fat Diet to Treate Obesity and Hyperlipidemia: A Randomized, Controlled Trial. Yancy et al. Annals of Int. Med. 2004; 140:769-777. Duke University

  8. A Low-Carbohydrate, Ketogenic Diet Versus a Low-Fat Diet to Treate Obesity and Hyperlipidemia: A Randomized, Controlled Trial. • Setting: • Outpatient research clinic • Participants: • 120 overweight, hyperlipidemic volunteers • Intervention: (24 weeks) • Low CHO • initially <20g/d, nutritional supplements, exercise recommendation, group meetings • Low Fat • < 30% Cal from fat, < 300mg cholesterol, energy deficit of 500-1000 Cal/d, exercise recommendation, group meetings

  9. After 12 weeks: LC diet lost 12 kg, LF diet lost 5.5 kg

  10. Low CHO group had: • greater decreases in TG • increases in HDL-C • greater decreases in TG:HDL ratio • but: 2 dropped out due to elevated LDL-C (184 to 283mg/dl @ 3mo., 182 to 219 mg/dl @ 1 mo., 30% had elevated LDL-C by >10% compared to 16% on LF diet

  11. A Low-Carbohydrate, Ketogenic Diet Versus a Low-Fat Diet to Treate Obesity and Hyperlipidemia: A Randomized, Controlled Trial. • Other findings: • Ketonuria • 86% positive at 2 weeks • 42% positive at 24 weeks • Body composition • expected fat mass lost • LC = 9.4 kg • LF = 4.8 kg • % of total weight as fat similar in LC and LF • Both groups blood pressure and pulse rate decreased (NS between groups)

  12. A Low-Carbohydrate, Ketogenic Diet Versus a Low-Fat Diet to Treat Obesity and Hyperlipidemia: A Randomized, Controlled Trial.Adverse Effects

  13. A Low-Carbohydrate, Ketogenic Diet Versus a Low-Fat Diet to Treat Obesity and Hyperlipidemia: A Randomized, Controlled Trial.Diet Composition

  14. A Low-Carbohydrate, Ketogenic Diet Versus a Low-Fat Diet to Treat Obesity and Hyperlipidemia: A Randomized, Controlled Trial. • Conclusions • “…a low-carbohydrate diet program had better participant retention and greater weight loss. During active weight loss, serum triglyceride levels decreased more and HDL-C increased more with the LC diet than with the LF diet.”

  15. A Randomized Trial of a Low-Carbohydrate Diet for Obesity G. Foster et al. NEJM 2003;348:2082-2090 U. Penn, U. Colo, Wash U., T. Jefferson U.

  16. A Randomized Trial of a Low-Carbohydrate Diet for Obesity • Setting • multi-center outpatient clinics • Participants • 63 obese subjects, random controlled trial, excluded diabetics • Intervention (1 year) • LC Diet • RD meeting, 20gCHO/d, gradually increased, Dr. Atkins’ book, ‘self-help’ • LF Diet • RD meeting, 1200-1800 Cal/d diet, 60% CHO, 25% fat, LEARN Program for Weight Management, ‘self-help’

  17. A Randomized Trial of a Low-Carbohydrate Diet for ObesityAttrition Rate

  18. A Randomized Trial of a Low-Carbohydrate Diet for Obesity • Conclusions • “LC diet produced greater weight loss … than did the conventional diet for the first six months, but the differences were not significant at one year.” • “LC diet was associated with greater improvement in some risk factors for CHD.” • “Adherence was poor and attrition high in both groups.”

  19. The Effects of Low-Carbohydrate versus Conventional Weight Loss Diets in Severely Obese Adults: One Year Follow-up of a Randomized Trial L. Stern et al. Ann Intern Med. 2004;140:778-785 Phil. VAMC, U. Penn, Drexel U.

  20. The Effects of Low-Carbohydrate versus Conventional Weight Loss Diets in Severely Obese Adults: One Year Follow-up of a Randomized Trial • Setting • outpatient clinic • Participants • 132 adults with BMI >35, 83% with diabetes or metabolic syndrome, RCT • Intevention (1 year) • LC diet • 30gCHO/day, weekly meeting for 4 weeks, monthly meetings for next 11 months • LF diet • reduce Cal by 500 Cal/day, fat < 30%

  21. % Cal from CHO: LC=33%, LF=50% % Cal from FAT: LC=57%, LF=34% SFA & Chol intake not different, Caloric intake in LC tended to be lower

  22. The Effects of Low-Carbohydrate versus Conventional Weight Loss Diets in Severely Obese Adults: One Year Follow-up of a Randomized Trial • Summary • Weight Loss • LC lost more weight at 6 months than LF • after 6 months, LC maintained weight lost, LF continued to lose weight • Serum Lipids • changes in TC and LDL-C were NS between groups • TG decreased more in LF than LC • HDL decreased less in LF than LC

  23. The Effects of Low-Carbohydrate versus Conventional Weight Loss Diets in Severely Obese Adults: One Year Follow-up of a Randomized Trial • Summary • Glycemic Control • no difference in glycemic control or insulin sensitivity between LC and LF • HbA1c in diabetics was lower in LC than LF • Diet • greater weight loss in LC may be due to lower caloric intake • LF was not truly low fat • SFA intake was not different in LF and LC • MUFA intake was higher in LC than LF

  24. The Effects of Low-Carbohydrate versus Conventional Weight Loss Diets in Severely Obese Adults: One Year Follow-up of a Randomized Trial • Conclusions: • “LC had more favorable overall outcomes at 1 year than did those on LF diets” • “Weight loss was similar, but effects on atherogenic dyslipidemia and glycemic control were still more favorable…”

  25. Low-Carb Diets:What have we learned? • Weight loss • LC loses more weight at 6 months but differences in weight loss with LF disappear at 12 months • difference in weight loss may be primarily due to caloric intake • Attrition • both LC and LF diets have high attrition rates • LF may be more due to lower rate of weight loss and ‘been there, done that’. • LC may be more due to adverse effects and unsatisfactory dietary restrictions.

  26. Low-Carb Diets:What have we learned? • Health Risk Factors • TC & LDL-C not different at 1 yr • due to weight loss difference, lack of difference in SFA intake • HDL-C higher in LC diets • low fat diets tend to lower HDL • TG lower in LC diets • less VLDL synthesis in LC • small differences in glycemic control, blood pressure

  27. Low-Carb Diets:What have we learned? • Diets • LF diets often not as low in fat as recommended • LC diets often higher in carbs than recommended and may contain less saturated fat than expected. • Future

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