A Randomized Trial of A Low Carbohydrate Diet for Obesity

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A Randomized Trial of A Low- Carbohydrate Diet
for Obesity

• Presented by
• Christopher Stevens Brodl
• Kevin McDermott
• Acacia Smith

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Obesity Facts (American Obesity Association)

• Youth 85 or 95 percentile
• Adults Greater or equal to 30 BMI
• 30.3 of children overweight (age 6-11)
• 15.3 obese (age 6-11)
• Over weight or obese child 10 to 14 with 1 parent
  overweight has 79 of becoming overweight or
  obese adult

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Childhood Obesity (American Obesity Association)
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Adult Obesity
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Current Fad Diets

• Atkins Diet
• Phase 1 Introduction
• - Restrict carbohydrates to 20g/day
• - Carbohydrate foods grains, fruits,
  vegetables, legumes, nuts
• - Obtain carbohydrates from salads and
  non-starchy vegetables
• Phase 2 On Going Weigh Loss
• - Increase carbohydrates to 25g/day first week,
  30g/day second week. Continue this pattern
  until weight loss stops.
• - Then subtract 5g/day to continue slow weight
  loss
• - Carbohydrates will be in form of fiber-rich
  foods

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Current Fad Diets

• Atkins (Continued)
• Phase 3 Pre-maintenance
• - Transition from weight loss to weight
  maintenance
• - Add 10g/week to diet each week as long as
  moderate weight loss continues
• Phase 4 Lifetime Maintenance
• - Select from a wide range of food while
  watching carbohydrates

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Fad Diets (Continued)

• The Zone
• - Favored diet in Hollywood several years ago
• - 1,100 calorie diet
• - Claims many small meals of 40 carb/30
  protein/30
  fat will cause loss of weight

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• Sugar Busters
• - Fringe diet that went mainstream with book
  publication
• - Implies sugar cause diabetes, risk factor for
  heart disease, and insulin causes weight gain
  (Tufts University)
• - Eliminate/reduce high glycemic foods

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• Eat Right For Your Type
• - Blood type dictates diet strategy
• South Beach Diet
• - Very similar to Atkins
• - Eat meats, cheese, bacon and eggs!
• - Most likely losing water, not fat
• - Claims to drop 13lbs in first 2 weeks
• 3,500cal/lb, therefore 45,500 more cal then
  consumed. Equals running a marathon for 2 weeks
  straight

10

• Total Slacker Diet
• - Eat chips, ice cream
• - Fudge, meats, etc
• - Claims to allow weight gain of greater than
  310lbs in 4 months!

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A Randomized Trial of a Low-Carbohydrate Diet for
Obesity

• Gary D. Foster, Holly R. Wyatt, James O. Hill,
  Brian G. McGuckin, Cerrie Brill, B. Selma
  Mohammed, Philippe O. Szapary, Daniel J. Rader,
  Joel S. Edman, Samuel Klein
• New England Journal of Medicine 2003 3482082-90

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A Randomized Trial of a Low-Carbohydrate Diet for
Obesity

• Introduction
• Atkins diet popular and long-lasting
• No published RCTs evaluating efficiency
• One year, multi-center trial comparing low- carb
  diet to conventional diet

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A Randomized Trial of a Low-Carbohydrate Diet for
Obesity

• Methods
• Subjects
• 63 (43 women, 20 men) obese
• not type 2 diabetic
• not taking lipid lowering medications
• not taking medications that affect body weight
• Study design
• random assignment to diet
• meet only once with RD before beginning program

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A Randomized Trial of a Low-Carbohydrate Diet for
Obesity

• Methods, continued
• Outcomes
• body weight
• urinary ketones
• serum lipoprotein concentrations
• oral glucose tolerance test
• insulin sensitivity assessment
• Analysis of samples
• Statistical analysis

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A Randomized Trial of a Low-Carbohydrate Diet for
Obesity

• Results
• Weight
• group on low-carb diet lost more weight than
  group on conventional diet
• 3 months (P0.001)
• 6 months (P0.02)
• not statistically significant at 12 months
  (P0.26)

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A Randomized Trial of a Low-Carbohydrate Diet for
Obesity

• Results, continued
• Attrition
• subjects completing study
• 3 months (49 total, 28 low-carb, 21 conventional)
• 6 months (42 total, 24 low-carb, 18 conventional)
• 12 months (37 total, 20 low-carb, 17
  conventional)
• lower adherence on conventional diet, but
  differences not statistically significant

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A Randomized Trial of a Low-Carbohydrate Diet for
Obesity

• Results, continued
• Urinary ketones
• no significant relationship between weight loss
  and ketosis at any time during study
• Blood pressure
• systolic did not change significantly in either
  group
• diastolic decreased in both groups
• no significant difference between groups
• Oral glucose tolerance test
• no significant differences between groups

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A Randomized Trial of a Low-Carbohydrate Diet for
Obesity

• Results, continued
• Serum lipoproteins
• Total
• significantly lower for conventional diet at
  month 3
• LDL
• significantly lower for conventional diet at
  month 3
• HDL
• significantly higher for low-carb diet at months
  6 12
• Triglycerides
• significantly lower for low-carb diet at months 3
  6

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A Randomized Trial of a Low-Carbohydrate Diet for
Obesity

• Discussion/Conclusion
• Greater weight loss on low carb diet
• significant at months 3 6, but not long-term
• weight loss approximates standard behavioral and
  pharmacological treatments
• Long-term adherence may be difficult
• Overall greater energy deficit in low-carb diet

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A Randomized Trial of a Low-Carbohydrate Diet for
Obesity

• Level of Evidence 2b
• Individual RCT
• Less than 80 follow up
• Grade of Recommendation B
• Consistent level 2 study

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DiscussionCurrent Research

• Positives
• Many RCTs show low-carb diets to promote
• More weight lost (1, 3)
• Better LDL, HDL and triglyceride levels (1,3)
• Better glucose control (1, 2)
• Lower CVD risk (3)
• than with a conventional low-fat diet.
• LIMITATIONS
• Short term, low adherence, small samples

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DiscussionCurrent Research

• Negatives
• Some RCTs report no difference or negative
  effects
• Atkins diet produces same weight loss and heart
  disease risk lowering benefits as Ornish, Zone
  and Weight Watchers (4)
• High-fat ketogenic diet as intervention for
  epilepsy induces decreased HDL and increased
  atherogenic lipoproteins in children (5)
• Low Carbohydrate diets increase fatigue during
  exercise (7)

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DiscussionCurrent Research

• Reviews
• Review on efficacy and safety published in
  JAMA (RCTs, 1966-2003, 4 days duration, includes
  107 articles with 3268 participants)
• participant weight loss while using
  low-carbohydrate diets was principally associated
  with decreased caloric intake and increased diet
  duration but not with reduced carbohydrate
  content. (6)

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DiscussionPosition of Health Professionals

• CDC, ADA, AAP and USDA
• Have not changed their recommendations (8, 9, 10,
  15)
• ADA Position Statement
• Results of two new studies on low-carbohydrate
  diets support the position of the American
  Dietetic Association that the most effective
  method of healthy lifelong weight management
  includes an eating plan that is based on complex
  carbohydrates such as whole grains, fruits and
  vegetables, moderate in protein and relatively
  low in fat, coupled with daily physical activity
  (9)

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DiscussionPosition of Atkins

• Atkins official website suggests
• Saturated fat is your friend (11)
• Insulin is your enemy (12)
• Diet tips (13)
• Instead of milk, have cream
• Instead of pasta, have sauteed spinach Mmmmm.
• More information at http//atkins.com

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Why Do We Diet

• Individual personally decides to change lifestyle
  to improve health
• - outward physical appearance secondary
• Individual seeks lifestyle change based upon
  medical advice
• - outward physical appearance secondary

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• Individual seeks to change outward physical
  appearance
• - health secondary (goal?)
• - more likely to fall for fad diets
• - more likely to fail diet
• - repeated diet attempts
• - why?

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Health Care Professionals

• Understand the patient/client needs
• Why are they dieting? (Health or image)
• Do they have realistic goals
• Select right program

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Discussion

• What do you think of this study and its
  implications?
• What additional research seems necessary?
• Is this just a fad diet?
• How do we counsel people with chronic disease in
  regard to starting such a diet?
• What about low-carbs for short term dieting?
• For the very obese, does the benefit of weight
  loss outweigh any potential hazards of the
  diet?

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Bibliography

• Layman DK, et al., A Reduced Ratio of Dietary
  Carbohydrate to Protein Improves Body Composition
  and Blood Lipid Profiles During Weight Loss in
  Adult Women, Journal of Nutrition, 2003. 133(2)
  411-17
• Gannon MC, et al., Dietary Protein Improves the
  Blood Glucose Response in Persons with Type 2
  Diabetes, American Journal of Clinical
  Nutrition, 2003. 78(4) 734-41
• Samaha FF, et al., A Low-Carbohydrate as
  Compared with a Low-Fat Diet in Severe Obesity,
  The New England Journal of Medicine, 2003.
  348(21) 2074-2081
• Dansinger ML, et al., One Year Effectiveness of
  the Atkins, Ornish, Weight Watchers and Zone
  Diets in Decreasing Body Weight and Heart Disease
  Risk, Presented at the American Heart
  Association Scientific Sessions November 12, 2003
  in Orlando Florida
• Kwiterovich PO, et al., Effect of a high-fat
  ketogenic diet on plasma levels of lipids,
  lipoproteins, and apolipoproteins in children,
  JAMA, 2003. 290(7) 912-20
• Bravata DM, et al., Review of the Efficacy and
  Safety of Low-Carbohydrate Diets, JAMA, 2003.
  289(14) 1837-1850
• Butki BD, et al., Effects of a
  carbohydrate-restricted diet on affective
  responses to acute exercise among physically
  active participants, Percept Mot Skills, 2003.
  96(2) 607-15
• CDC Health and Nutrition Website
  http//www.cdc.gov/nccdphp/dnapa/index.htm
• ADA Website http//www.eartright.org/Public/
• AAP, Sports Shorts Guidelines for parents and
  athletes the dos and donts of sports
  nutrition, Issue 6
• Heimowitz, Colette M.S. Big Fat Lies,
  http//atkins.com/Archive/2001/12/21-587266.html
• Atkins.com The Role Insulin Plays in Obesity,
  http//atkins.com/Archive/2001/12/15-223550.html
• Atkins.com Selecting the Right Carbohydrates,
  http//atkins.com/Archive/2001/12/15-683944.html
• ADA position statement on Food and Nutrition
  Misinformation, http//www.eatright.org/Public/Gov
  ernmentAffairs/92_adar0202.cfm
• USDA Food Guide Pyramid http//www.usda.gov/cnpp/p
  yramid-update/index.html