Popular Diets

Gil C. Grimes, MDAssistant Professor Family Medicine

Texas A&M HSC COMScott and White Family Medicine Residency

April 9th 2005

Objectives Describe the obesity rates in America Describe patient’s view of physicians

role Describe the three basic diet types Recognize key elements for weight loss Compare the effectiveness of various

dietary approaches Describe the role of exercise

Is the Horse out of the Barn?

Obesity Epidemic

Obesity US 1991

[Level 2b]

Obesity US 1992

[Level 2b]

Obesity US 1993

[Level 2b]

Obesity US 1994

[Level 2b]

Obesity US 1995

[Level 2b]

Obesity US 1996

[Level 2b]

Obesity US 1997

[Level 2b]

Obesity US 1998

[Level 2b]

Obesity US 1999

[Level 2b]

Obesity US 2000

[Level 2b]

Obesity US 2001

[Level 2b]

Texas 2001

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

White Black Hispanic Multiracial Other

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Overweight

Obese

What to do? Several programs available to help

Commercial help (that has been studied) Weight Watcher Health Management Resources eDiets.com Take Off Pounds Sensibly OPTIFAST

Do it yourself Atkins Ornish Zone South Beach

Patient’s Perception Patients surveyed in 2 Primary care

practices(1)

BMI <25 Wt loss is important to me 84% Wt affects my happiness 59% Wt affects my health 24%

BMI 25-30 Wt loss is important to me 78% Wt affects my happiness 54% Wt affects my health 46%

BMI >30 Wt loss is important to me 95% Wt affects my happiness 67% Wt affects my health 80%

1) J Fam Pract. 2001 Jun;50(6):513 Level 3

Patient’s Perception Best Method of Wt Loss for

Me BMI <25 BMI 25-30

BMI >30

Exercise 87% 94% 83%

Diet 87% 80% 79%

Ref to Wt program

9% 20% 35%

Wt loss products or pills

14 % 12% 20%

J Fam Pract. 2001 Jun;50(6):513 Level 3

Patient’s Perception Current Doctor has helped

Lost wt in past BMI <25 6% BMI 25-30 11% BMI >30 26%

Lose wt in the future BMI <25 49% BMI 25-30 63% BMI >30 84%

J Fam Pract. 2001 Jun;50(6):513 Level 3

Patient’s Perception Counseling on realistic goals Counseling on diets Counseling on the cause of

obesity Counseling on exercise Encouragement

J Fam Pract. 2001 Jun;50(6):513 Level 3

Basic Advice Sustainable weight loss (1)

Slow steady 1-2 lbs a week 500 cal/day reduction

Exercise (2)(3)

Key to sustained weight loss In combination with reduced calorie

synergistic effect

1) Obesity from DynaMed Level 52) Clinical Evidence 2001 Dec;6;43 Level 2

3) Arch Intern Med. 2000 Jul 24;160(14):2177 Level 1c

Basic AdviceCalorie balance is the major determinant of weight loss. Diets that reduces caloric intake result in weight loss. In the absence of physical activity, the optimal diet for weight loss contains ~1400 to 1500 kcal/d, regardless of the macronutrient composition .(Level A)

Popular Diets: A Scientific ReviewObesity Research Vol 9 Supp 1 March

2001

Characterization of Diets Typical American (% energy)

Fat 85 gm 35% Carbohydrates (CHO) 275 gm 50% Protein 82.5 gm 15% 2200 kcal/day

Obs Research 2001 March 1;9(supl 1)1s Level 1a

Characterization of Diets Atkins and South Beach (% energy)

High fat 94 gm 60% Low CHO <100g/d

Actual 35 gm 10% High protein 105 gm 30% 1414 kcal/day

Obs Research 2001 March 1;9(supl 1):1S

Characterization of Diets DASH and Weight Watchers (%

energy) Moderate fat 40 gm 20-30% Balanced nutrient reduction diets High in CHO 218 gm 60% Moderate in protein 54 gm 15% 1450 kcal/day

Obs Research 2001 March 1;9(supl 1):1S

Characterization of Diets Ornish and Pritkin diet (% energy)

Low fat 24 gm 15% Very low fat 16 gm 10% Very high CHO 25-271 gm 65-75% Moderate protein 54-72 gm 15-20 % 1450 kcal/day

Obs Research 2001 March 1;9(supl 1):1S

Philosophy of Low Carb High Carbohydrate intake promotes cycle

Promotes increased insulin levels Result in increase Triglycerides Increased fat deposition Insulin resistance and hyperinsulinemia

Reduced serotonin Decreased sense of satiety Drives more over-eating

Restricted CHO produces ketosis Decreases insulin levels Promotes fat consumption

Dr. Atkins New Diet Revolution

South Beach Angle Same Low CHO basis

Introductory period of sever CHO restriction Subsequent CHO are allowed Key is low glycemic index CHO

Low glycemic index foods encouraged Whole grains Vegetables Certain fruits and nuts

High glycemic index food result in insulin surge Insulin surge leads to vicious cycle Choose the right fats (limit trans-fatty foods) Lean protein sources

The South Beach Diet Plan

Atkins Decreased consumption

Intake of protein and fat is self-limiting Overall reduction in caloric intake (Level

A) Result in ketosis (Level B) Key factors for weight loss

Duration of diet (p=0.002) Caloric restriction (p=0.03) Not carbohydrate restriction (p=0.9)

JAMA 2003 Apr 9;289(14):1837 Level 1a

Low vs. High Carbs Low-carbohydrate diet more effective

than low-fat diet at 1 year 63 obese nondiabetic patients (mean BMI

34) low-carbohydrate diet (Atkins diet) low-fat diet (1200-1500 kcal/day for women,

1500-1800 kcal/day for men) for 1 year 40% dropout rate

39% low-carbohydrate 43% low-fat group

NEJM 2003 May 22;348(21):2082 Level 2

Low vs. High Carbs analysis using baseline data in place

of current weight for dropouts (assuming regain of any weight lost) greater weight loss with low-

carbohydrate diet 3 months (-6.8 kg vs.. -2.7 kg) 6 months (-7 kg vs.. -3.2 kg)

but not statistically significant at 12 months (-4.4 kg vs.. -2.5 kg)

NEJM 2003 May 22;348(21):2082 Level 2

NEJM 2003 May 22;348(21):2082 Level 1c

Low vs. High Carbs 120 obese volunteers with hyperlipidemia

low-carbohydrate, ketogenic diet plus nutritional supplement; initially carbohydrate < 20 g/day

low-fat, low-cholesterol, reduced-calorie diet; < 30% energy from fat, cholesterol < 300 mg/day, calorie deficit 500-1,000 kcal/day

Both groups had exercises and group meetings

Ann Intern Med. 2004 May 18;140(10):769 Level 2

Low vs. High Carbs Study limitations

follow-up only 24 weeks high dropout rates (24% low-carbohydrate vs..

43% low-fat group, p = 0.02, NNT 5 for tolerability)

analyses both with (intent-to-treat) and without (study completers) not clearly described

low-carbohydrate group (but not low-fat group) received nutritional supplement, and ketonuria tests to assess (and improve) compliance

Ann Intern Med. 2004 May 18;140(10):769 Level 2

Low vs. High Carbs Mean weight loss at 24 weeks,

comparing low-carbohydrate vs.. low-fat group -12 kg vs.. -6.5 kg (p < 0.001) -12.9% vs.. -6.7% (p < 0.001) 61% vs.. 23% completed study and

had at least 10% weight loss (p < 0.001, NNT 2.6)

Ann Intern Med. 2004 May 18;140(10):769 Level 2

Low vs. High Carbs Adverse effect significantly more

common with low-carbohydrate vs.. low-fat diet constipation (68% vs.. 35%, NNH 3) headache (60% vs.. 40%, NNH 5) halitosis (38% vs.. 8%, NNH 3.3) muscle cramps (35% vs.. 7%, NNH 3.6) diarrhea (23% vs.. 7%, NNH 6.3) general weakness (25% vs.. 8%, NNH 5.9) rash (13% vs.. 0, NNH 7.7)

Low Fat Approach Fat-restricted diets are no more effective

(and are possibly less effective) than calorie-restricted diets systematic review of randomized trials comparing fat-restricted diets vs.. control diets

for weight loss in adults with BMI > 25 kg/m2 followed at least 6 months

no significant differences at 6 months (4 trials), 12 months (5 trials) or 18 months (3 trials)

but fat-restricted diets were associated with less weight loss in each of these comparisons

Cochrane Library 2002 Issue 2:CD003640

Low Fat Approach Low-fat diet can promote weight loss, even

in absence of caloric restriction meta-analysis of 16 studies with 1,910 subjects comparing low-fat/high-carbohydrate diet in

absence of energy restriction (i.e. ad libitum, no caloric restriction) with control group of either maintenance of regular diet or diet with fat content similar to general population

diets had 47% vs.. 57% fat content low-fat diet associated with weight loss of 3.2 kg,

or about 7 pounds

Int J Obes 2000;24;1545 Level 1a

The Big Comparison 160 overweight or obese adults aged

22-72 years Mean BMI 35, range 27-42 Comorbidities hypertension, dyslipidemia

or fasting hyperglycemia Randomized to a diet Big encouragement for first two months Wt loss correlated with self-reported

dietary adherence

JAMA 2005 Jan 5;293(1):43 Level 1c

The Big Comparison Self Reported compliance

JAMA 2005 Jan 5;293(1):43 Level 1c

The Big Comparison Atkins diet (carbohydrate restriction)

Drop out rate 47% Wt loss 2.1kg

Ornish diet (fat restriction) Drop out rate 50 % Wt loss 3.3 kg

Weight Watchers diet (calorie restriction) Drop out rate 35% Wt loss 3 kg

Zone diet (macronutrient balance) Dropout rate 35% Wt loss 3.2 kg

JAMA 2005 Jan 5;293(1):43 Level 1c

JAMA 2005 Jan 5;293(1):43 Level 1c

Changes in HDL, CRP, Insulin

JAMA 2005 Jan 5;293(1):43 Level 1c

Exercise

Role of Exercise Exercise may be more effective than diet at equivalent

“doses” 52 obese men (mean BMI 31) RCT for 3 months

Diet-induced weight loss (eating 700 kcal/day less) Exercise-induced weight loss (running off 700 kcal/day) Exercise without weight loss Control

Body weight decreased by 7.5 kg (8%) in both weight loss groups and did not change in other groups

Total fat decreased in both weight loss groups (p < 0.001)

Average reduction 1.3 kg greater in exercise-induced weight (p = 0.03)

Abdominal and visceral fat also decreased in exercise without weight loss group

Ann Intern Med 2000 Jul 18;133(2):92 Level 1c

Role of Exercise Exercise promotes weight loss in dose-

dependent fashion low amount of exercise (walking 30

minutes/day) adequate to avoid weight gain and higher amounts promote weight loss

182 sedentary, overweight men and women aged 40-65 years with mild to moderate dyslipidemia were advised to maintain existing diet for 8 months

Arch Intern Med. 2004 Jan 12;164(1):31 Level 1c

Role of Exercise Randomized

High-amount/high-intensity exercise (caloric equivalent to jogging 20 miles/week)

High-amount/high-intensity exercise (equivalent to jogging 12 miles/week)

Low-amount/moderate-intensity exercise (equivalent to walking 12 miles/week)

120 (66%) patients completed trial weight change +1.1 kg in control group -1.1 to -1.3 kg with low-amount exercise -3.5 kg with high-amount exercise

Arch Intern Med. 2004 Jan 12;164(1):31 Level 1c

Take Home Points Any diet can work Must set reasonable goals Exercise is key for maintenance Provide ongoing encouragement Celebrate small successes Remember, maintenance of weight

loss requires a change of lifestyle

Thanks