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Popular Weight Loss Diets: What

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Title: Popular Weight Loss Diets: What


1
Popular Weight Loss Diets Whats The Evidence?
  • Low Carbohydrate Diets
  • CJ Segal-Isaacson, EdD, RD
  • High Protein Diets
  • Manny Noakes, PhD
  • Low Fat Diets
  • Keith Ayoob, EdD, RD

Application for CME credit has been filed with
the American Academy of Family Physicians.
Determination of credit is pending The AAFP is
accredited by the Accreditation Council for
Continuing Medical Education (ACCME) to sponsor
Continuing Medical Education.
2
Focus of Each Talk
  • Define Diet
  • Present The Evidence for Its Weight Loss Effects
  • Present The Evidence for Cardiovascular and
    Insulin Sensitivity Effects
  • Conclusions

3
Low Carbohydrate Weight Loss Diets
CJ Segal-Isaacson, EdD RD Assistant
Professor Division of Nutrition and Health
Behavior Department of Epidemiology and
Population Health Albert Einstein College of
Medicine, Yeshiva University
4
Cathy...On Low Carbohydrate Dietsby Cathy
Guisewite
5
Different Strokes For Different Folks
  • One size does not fit all with weight loss diets
    --- we need a variety of approaches to combat the
    obesity epidemic.
  • It is possible that lower carbohydrate diets may
    be more effective for people with Metabolic
    Syndrome.1-2
  • Samaha FF, Iqbal N, Seshadri P, et al. N Engl J
    Med. May 22 2003 348 (21) 2074-2081.
  • Eckel RH, Drazin B. J. Investigative Med.
    51Suppl. 2.2003 S383.

6
Popular Low Carbohydrate Diets
  • The Dr. Atkins Diet (Has four levels)
  • Induction (lt20 g of carbs)
  • Ongoing Weight Loss (Typically 25-45 grams carbs)
  • Premaintenance (Typically 30-60 grams carbs)
  • Maintenance (Typically 40-100 grams carbs)
  • Carbohydrate Addicts Diet
  • Protein Power
  • Cyclic Ketogenic
  • The Zone Diet (30-40-30)
  • Neanderthin

7
2001 International Low Carbohydrate Weight Loss
Survey
  • Internet-based questionnaire.
  • Data collected June-July 2001.
  • 6,088 low carbohydrate dieters responded.
  • Segal-Isaacson CJ, Segal-Isaacson AE,
    Wylie-Rosett, J. The Journal
  • of The American Dietetic Association. 2002. 102
    S45.

8
  • Who Responded To The Survey?
  • Questionnaire Was Web-based, With Online Consent
    Form
  • SAMPLE SIZE 6,088 Low Carbers Responded,
    June-July 2001
  • GENDER 75.4 Women 24.6 Men
  • RACE 90.5 White 3.5 Hispanic 2.7 Black
    3.3 Other
  • MAIN GEOGRAPHIC LOCATIONS 87.5 USA 0.5
    Canada
  • HIGHEST EDUCATIONAL DEGREE ATTAINED
  • 0.5 Elementary School
  • 29.4 High School
  • 21.3 Associates Degree
  • 31.5 Bachelors Degree
  • 13.0 Masters Degree
  • 4.4 Doctoral Degree

9
The Three Most Common Low Carb Diets 2001 Low
Carbohydrate Weight Loss Diet Survey)N 5177
Segal-Isaacson CJ, Segal-Isaacson AE,
Wylie-Rosett, J. The Journal of The American
Dietetic Association. 2002. 102 S45.
10
Typical Macronutrient Profile of Low
Carbohydrate Diets
  • Nutrient Percentage of Calories
  • Carbohydrate 5-25
  • Protein 25-35
  • Fat 55-65
  • Alcohol lt5 (metabolized mostly as fat)
  • Macronutrient percentages may distort what
    actually occurs in low carbohydrate dieting.
  • Due to increased satiety, less food may be eaten.
    Carbohydrate intake is reduced while fat and
    protein intake may only moderately increase.
    Calories are often substantially reduced.

11
Typical Low Carbohydrate Dinner
Food Portion Size Calories Carbs (g) Fat (g) Protein (g)
Roast Chicken 1/4 Chicken 306 0 19 31
Green Beans with Sunflower Seeds and Olive Oil 3/4 Cup 102 9 9 3
Green Salad with Italian Dressing 2 Cups with 1 Tablespoons 74 4 4 2
Diet Gelatin with Whipped Cream 1 Cup with 1 Tablespoon 70 2 6 3
TOTALS 550 15 38 39
12
Foods On Low Carbohydrate Diets
  • Unrestricted Foods Poultry, fish, meat, eggs,
    protein powders, low-starch vegetables,
    artificial sweeteners, diet gelatins, oils,
    butter.
  • Mildly Restricted Foods Cheeses, tofu, nuts,
    berries, yogurt, milk.
  • Moderately Restricted Foods Other fruits, cream,
    legumes, carbohydrate-reduced soy and grain
    products.
  • Excluded Foods Grains, bread, rice, potatoes,
    pasta, cereals, candies, pastries, cookies, pies.

13
Micronutrient Intake
  • Generally adequate for most vitamins and
    minerals.
  • If carbohydrates are severely restricted (lt20
    grams)
  • Diet may be low in Vitamin C, Beta Carotene and
    Fiber.
  • Potassium and sodium levels should be monitored
    and may need to be supplemented during the first
    month of the diet, as they are additionally
    excreted in urine.

14
Lets Switch Gears..
  • And Talk About Ketogenic,
  • Very Low Carbohydrate Diets

15
The Role of Ketones In Human Physiology
  • Diets containing less than 10-15 carbohydrates
    usually cause modest amounts of urinary ketosis.
  • Ketones are produced as fuel from metabolized
    fats (acetyl-CoA) when carbohydrate-dervived
    pyruvate is low.
  • Enzymes are present within all cells to convert
    ketones into fuel except in erythrocytes,
    cornea, lens and retina.
  • Adapted from a slide by Eric Westman, MD.

16
The Role of Ketones (continued)
  • Serum ketone levels are relatively low during low
    carbohydrate diets
  • Fed State 0.1 mmol/L
  • Overnight Fast 0.3 mmol/L
  • Low Carb Ketogenic Diet 1-3 mmol/L
  • gt20 Days Fasting 10 mmol/L
  • Diabetic Ketoacidosis gt25 mmol/L
  • Meckling et al. Can J Physiol Pharmacol
    2002801095-1105. Sharman MJ et al. J Nutr
    20021321879-1885.
  • Adapted from a slide by Eric Westman, MD.

17
Short-Term Weight Loss Studies
  • Early studies comparing low carb to low fat diets
    often used caloric levels of lt1000 cal/day. These
    very low calorie studies did not show a weight
    loss difference between diets.
  • Most comparison studies today are using diets
    with moderate calorie deficits of 500-700
    kcal/day.
  • The carbohydrate intake in current studies is
    usually about that of the Atkins Induction Diet
    (most strict level) and is generally ?30 g/day.
  • Yang MU, Van Itallie TB. J Clin Invest. Sep
    197658(3)722-730.

18
Foster GD, Wyatt HR, Hill JO, et al. N Engl J
Med. May 22, 2003348(21) 2082-2090.
  • First published RCT. Six month trial with
    follow-up to one year. Average baseline BMI of 34
    kg/m2.
  • Atkins Diet (all 4 levels) with ad lib kcal but
    controlled carbohydrate intake.
  • Low cal diet 1200-1500 kcal for women and
    1500-1800 kcal for men. Energy intake was 60
    carb, 25 fat and 15 protein.
  • N 63 43 women and 20 men. Low carb arm33 and
    Low Cal arm30. Average age is 44 years.
  • No type 2 diabetes, lipid-lowering meds or other
    serious illness.

19
Weight Loss Results of Foster et al.
  • Better participant retention in low carb arm at
    all measurement points -- 3,6 12 months,
    plt0.05.
  • Did not report on actual calorie intakes of
    subjects.
  • Weight loss significantly better in low carb
    group at 3 and 6 months but not at 12 months
  • 3 Month Wt Loss
  • Low Carb -6.8 5.0 Low Cal -2.7 3.7
    (plt0.001).
  • 6 Month Wt Loss
  • Low Carb -7.0 6.5 Low Cal -3.2 5.6
    (plt0.02).
  • 12 Month Wt Loss
  • Low Carb -4.4 6.7 Low Cal -2.5 6.3
    (plt0.26).

20
Weight Loss Results of Foster et al.
From p. 2085 of Foster et al., 2003 NEJM.
21
Lipid Results of Foster et al.
From p. 2088 of Foster et al., 2003 NEJM.
22
Blood Pressure and Insulin Sensitivity Results
of Foster et al.
  • Equivalent improvements for both groups at 3,6
    and 12 months for
  • Systolic and diastolic blood pressure.
  • Area under the glucose curve (OGT).
  • Area under the insulin curve (OGT).
  • Insulin sensitivity.

23
Summary Of Results From Short-Term Studies
  • Low carb diets consistently produced more weight
    loss in RCTs that did not control the calorie
    levels between diets.
  • Brehm BJ, Seeley RJ, Daniels SR, D'Alessio DA. J
    Clin Endocrinol Metab. Apr 200388(4)1617-1623.
  • Foster GD, Wyatt HR, Hill JO, et al. N Engl J
    Med. May 22, 2003348(21) 2082-2090.
  • Samaha FF, Iqbal N, Seshadri P, et al. N Engl J
    Med. May 22 2003348(21)2074-2081.
  • Westman EC, Yancy WS, Guyton JS. AHA. Nutrition
    Abstracts. Circulation (Supplement II).
    2002106(19).

24
Summary Of Results From Short-Term Studies cont.
  • In a recent study where the calories were kept
    the same, the weight loss was fairly comparable
    between the Atkins Diet and the DASH Diet
    although there was a trend for greater weight
    loss by 1.3 kg in the Atkins group.
  • Due to the small sample size in each group (n13)
    in the Atkins group and (n12) in the DASH group,
    and the short time the results are not
    definitive.
  • Stadler D, Burden V, McMurry M, Gerhard G,
    Connor W, Karanja N. Presentation at Experimental
    Biology annual conference, April, 2003.
  • Current RCT trials at the Albert Einstein College
    of Medicine and Harvard University are also
    trying to answer the question of diet composition
    per se affects weight loss rates.

25
Summary Of Results From Short-Term Studies cont.
  • Low carbohydrate diets may produce more satiety
    and reduced appetite . leading to decreased
    caloric intake.
  • Increased satiety may explain generally lower
    drop-out rates in low carbohydrate groups. If
    there is increased satiety, is it due to protein?
  • Brehm BJ, Seeley RJ, Daniels SR, D'Alessio DA. J
    Clin Endocrinol Metab. Apr 200388(4)1617-1623.
  • Foster GD, Wyatt HR, Hill JO, et al. N Engl J
    Med. May 22, 2003348(21) 2082-2090.
  • Samaha FF, Iqbal N, Seshadri P, et al. N Engl J
    Med. May 22 2003348(21)2074-2081.
  • Westman EC, Yancy WS, Guyton JS. AHA. Nutrition
    Abstracts. Circulation (Supplement II).
    2002106(19).

26
Summary Of Results From Short-Term Studies cont.
  • A low carbohydrate weight loss diet produced a
    greater reduction than a low fat weight loss diet
    in the inflammatory markers C-reactive protein
    and serum amyloid A. Both markers are associated
    with cardiovascular risk.
  • Unclear whether the better reduction in
    inflammatory markers with the low carb diet was
    related to greater weight loss in the low carb
    group or was independent of this effect.
  • OBrien KD, Brehm BJ, Seeley RJ, Werner M,
    Daneils, D,DAlessio DA. AHA. Nutrition
    Abstracts. Circulation .(Supplement II).
    2002106(19).

27
Summary Of Results From Short-Term Studies cont.
  • Preliminary evidence from 1 month study showed
    greater urinary acid and calcium excretion among
    overweight volunteers (BMI 29.4 kg/m2) on a
    very low carbohydrate diet compared to their
    normal diet.
  • Study found no metabolic acidosis. It did find
    increased urinary acid excretion that was due to
    the increase in sulfur-containing amino acids
    from protein foods and acidic ketone bodies. This
    may increase the risk of renal stones.
  • Reddy ST, Wang CY, Sakhaee K, Brinkley L, Pak CY.
    Am J Kidney Dis. Aug 200240(2)265-274.

28
Summary Of Results From Short-Term Studies cont.
  • Increased calcium excretion without compensatory
    increase in intestinal calcium absorption may
    lead to bone loss.
  • However, its unclear whether if a low carb diet
    was used for a longer time period, whether there
    might be physiological adaptation to it. Longer
    term studies are needed.
  • Do populations such as the Eskimos who have
    survived on very low carb diets show such
    adaptations?
  • Reddy ST, Wang CY, Sakhaee K, Brinkley L, Pak CY.
    Am J Kidney Dis. Aug 200240(2)265-274.

29
Summary Of Results From Short-Term Studies cont.
  • Low Carbohydrate Weight Loss Diets may work
    better for people with Metabolic Syndrome --
    better weight loss, and greater improvements in
    triglyceride levels. Better weight loss tracks
    with insulin sensitivity improvements.
  • Insulin sensitive participants lost more weight
    on the LF/HC diet compared to the HC/LC diet
    (13.56 1.60 kg compared to 6.12 1.13 kg,
    plt0.01). Also there was a trend for improvements
    in insulin sensitvity in already IS participants
    on the LF/HC diet.

30
Summary Of Results From Short-Term Studies cont.
  • Insulin resistant participants lost more weight
    on the HF/LC diet compared to the LF/HC diet
    (11.46 1.37 kg compared to 6.52 0.98 kg,
    plt0.05). Also there was a trend for improvements
    in insulin sensitvity in insulin resistant
    participants on the HF/LC diet.
  • Samaha FF, Iqbal N, Seshadri P, et al. N Engl J
    Med. May 22 2003348(21)2074-2081.
  • Eckel RH, Drazin B. J. Investigative Med.
    51Suppl 2.2003 S383.

31
Summary Of Results From 2001 Low Carbohydrate
Weight Loss Survey, N6,088Segal-Isaacson CJ,
Segal-Isaacson AE, Wylie-Rosett, J. The Journal
of The American Dietetic Association. 2002. 102
S45.
  • More than half of the respondents (55.9) were
    currently dieting to lose weight and their BMI
    was higher than those who were not trying (31.2 ?
    7.8 compared to 29.8 ? 7.6 p lt 0.001).
  • Those who were not currently dieting to lose
    weight reported they had lost an average of 36.2
    ? 25.6 lbs but had wanted to lose 56.3 ? 41.3
    lbs.
  • The amount of weight these respondents reported
    they kept off for at least one year was at least
    11-20 lbs for 53.2 of the respondents and at
    least 21-30 lbs for 37.4 of the respondents.

32
Summary Of Results From 2001 Low Carbohydrate
Weight Loss Surveycont.
  • Most respondents modified the diet they chose
    (60.2). The most common modifications were
    adding more vegetables (29.0), fruit (12.4) or
    occasionally going off the diet (32.7).
  • The three most common diet likes were not feeling
    hungry (87.5) or deprived (85.6) and losing
    weight easily (74.1).
  • The three most common diet dislikes were bad
    breath (30.9), light headedness (15.0) and
    nausea (8.3).

33
Current Low Carbohydrate Research At The Albert
Einstein College of Medicine
  • The CCARB Study First long-term study on low
    carbohydrate dieters. Internet-based -- will
    follow each participant for at least three years.
    More than 50 of participants have objectively
    documented their weight and height through their
    healthcare provider. Will also assess lipid
    values in a subset. Website address is
    http//epi.aecom.yu.edu/ccarbs
  • The Metabolic Impact Study Pilot controlled
    feeding study that uses isocaloric-isonitrogenous
    diets to determine whether a very low
    carbohydrate diet burns body fat more quickly
    than a moderate low fat diet. Uses stable
    isotopes to trace whether ingested fats are
    oxidized or stored indirect calorimetry to
    measure energy expenditure and and MRI to measure
    body fat distribution.

34
Current Low Carbohydrate Research At The Albert
Einstein College of Medicine cont.
  • The Diabetes Dietary Study Study on 74 adults
    with type 2 diabetes who also take insulin. Study
    will compare a one year trial of an Atkins-style
    low carbohydrate diet to the low fat diet used in
    the Diabetes Prevention Project.
  • Call 718 430-2161 for more information on any of
    the three studies or email at isaacson_at_aecom.yu.ed
    u .

35
Annotated Bibliography
36
  • Brehm BJ, Seeley RJ, Daniels SR, D'Alessio DA.
  • J Clin Endocrinol Metab. Apr 200388(4)1617-1623
    .
  • Six month RCT with 53 obese women comparing a low
    carb (lt20 g/day for first two weeks then 40-60
    g/day) to a low calorie-30 fat diet with
    calories at an estimate of resting energy
    expenditure.
  • Weight loss was greater in the low carb group
    8.5 1.0 kg compared to 3.9 1.0 kg.
  • Blood pressure was normal in both groups and
    remained so during the trial.
  • Lipids were normal in both groups but improved
    with weight loss in both groups.
  • Fasting insulin and glucose decreased similarily
    in both groups.

37
  • Eckel RH, Drazin B. J. Investigative Med.51Suppl
  • 2.2003 S383.
  • Controlled 16 week feeding trial with 24 obese
    adults who were randomized to either a low
    fat/high carb or a high fat/low carb diet.
    Participants were also stratified by insulin
    levels lt10 ?U/ml insulin sensitive
    gt15 ?U/ml insulin resistant.
  • Diets were matched for energy with a 400 kcal
    deficit. The composition of the low fat/high carb
    diet (LF/LC) was 60 CHO, 20 fat, 20 protein.
    The composition of the high fat/low carb diet
    (HF/LC) was 40 CHO, 40 fat, 20 protein.
  • All participants lost at least 5.82 kg.
  • Insulin sensitive participants lost more weight
    on the LF/HC diet compared to the HC/LC diet
    (13.56 1.60 kg compared to 6.12 1.13 kg,
    plt0.01). Also there was a trend for improvements
    in insulin sensitvity in already IS participants
    on the LF/HC diet.

38
  • Eckel RH, Drazin B. J. Investigative Med.51Suppl
  • 2.2003 S383 cont.
  • Insulin resistant participants lost more weight
    on the HF/LC diet compared to the LF/HC diet
    (11.46 1.37 kg compared to 6.52 0.98 kg,
    plt0.05). Also there was a trend for improvements
    in insulin sensitvity in insulin resistant
    participants on the HF/LC diet.
  • There was no relationship between baseline
    fasting insulin levels and weight loss.
  • The improvement in insulin sensitivity predicted
    the amount of weight loss, r0.71.
  • No significant changes in LDL or HDL.
    Triglycerides decreased in everyone but insulin
    resistant participants on the LF/HC diet.
  • A high fat, low carbohydrate diet may be a more
    effective weight loss diet for insulin resistant
    obese people.

39
  • OBrien KD, Brehm BJ, Seeley RJ, Werner M,
    Daneils,
  • D,DAlessio DA. AHA. Nutrition Abstracts.
    Circulation
  • (Supplement II). 2002106(19).
  • RCT of 43 obese adults comparing effects of low
    fat diet versus low carbohydrate diet on the
    inflammatory markers C-reactive protein and serum
    amyloid A.
  • Six month trial with adlib diet.
  • Low fat diet n22, Energy distribution CHO
    55 Fat 30 Protein 15
  • Low carb diet n21, Energy distribution CHO
    lt10 no other restriction.

40
  • OBrien KD, Brehm BJ, Seeley RJ, Werner M,
    Daneils,
  • D,DAlessio DA. AHA. Nutrition Abstracts.
    Circulation
  • (Supplement II). 2002106(19). Continued.
  • More weight loss in low carb group 6 months -7.3
    4.7kg versus -2.8 4.4 kg in low fat group.
  • No reduction in inflammatory markers in low fat
    group but significant reduction in low carb group
    at 6 months -33 reduction in CRP and -21 in
    serum amyloid A at 3 months.
  • Unclear from abstract to what extent reduction in
    inflammatory markers was related to weight loss.

41
  • Reddy ST, Wang CY, Sakhaee K, Brinkley L, Pak CY.
  • Am J Kidney Dis. Aug 200240(2)265-274.
  • Purpose of study was to evaluate the effect low
    carb, high protein diets on acid-base balance,
    calcium metabolism and stone formation.
  • 10 volunteers with an average BMI of 29.4 kg/m2.
  • Eight week trial 2 weeks normal diet, 2 weeks at
    lt20 g/day of carbs and 4 weeks at lt35 g/day.
  • No metabolic acidosis.
  • Increased urinary acid excretion due to
    sulfer-containing amino acids from protein foods
    as well as acidic ketone bodies.

42
  • Reddy ST, Wang CY, Sakhaee K, Brinkley L, Pak CY.
  • Am J Kidney Dis. Aug 200240(2)265-274.
    Continued.
  • Also Increased urinary calcium excretion without
    compensatory increases in intestinal calcium
    absorption.
  • No changes in serum potassium, chloride, CO2,
    calcium or phosporus but slightly lower sodium
    levels.
  • No change in urinary uric acid, oxalate, sodium,
    potassium or total volume of urine.
  • Authors conclude the net increase in acid (50
    mEq/d) through the combined effects of a high
    protein-low carbohydrate diet may increase risk
    for renal stones and bone loss.

43
  • Samaha FF, Iqbal N, Seshadri P, et al. N Engl J
    Med. May
  • 22 2003348(21)2074-2081.
  • 132 severely obese adults with an average BMI of
    43 kg/m2.
  • 39 participants had diabetes and 43 metabolic
    syndrome.
  • Six month RCT at a Phil. V.A. hospital.
  • Low Carb lt30 g/day of carbs with no calorie
    restriction.
  • Low Fat / LowCal 30 dietary fat with 500
    calorie deficit.
  • Dietary compliance evaluated with 24 recalls.

44
  • Samaha FF, Iqbal N, Seshadri P, et al. N Engl J
    Med. May
  • 22 2003348(21)2074-2081. Continued.
  • More weight lost on low carb diet 5.8 8.6 kg
    compared to 1.9 4.2 kg p0.002.
  • Triglycerides decreased more in the low carb
    group.
  • No other lipid differences.
  • Fasting glucose decreased more in low carb group
    among its diabetic subjects with concommittant
    reductions in DM meds.
  • Insulin sensititivity improved more in low carb
    group (this was only measured in non-diabetic
    participants of both groups).

45
  • Stadler D, Burden V, McMurry M, Gerhard G,
  • Connor W, Karanja N. Presentation at Experimental
  • Biology annual conference, April, 2003.
  • Trial matched the caloric levels of 13
    participants on the Atkins diet with another 12
    participants on the DASH diet.
  • The average ad lib calorie reduction on the
    Atkins diet was 68 of usual and the calorie
    intake of participants on the DASH diet was
    matched at 67 of usual.
  • The participants were given meals prepared in a
    metabolic kitchen for 42 days.
  • Although weight loss was not significantly
    different between the two diet groups, there was
    a trend for greater weight loss in the Atkins
    group by 1.3 kg.

46
  • Westman EC, Yancy WS, Edman JS, Tomlin KF,
    Perkins
  • CE. Am J Med. Jul 2002113(1)30-36.
  • One-armed trial.
  • 41 of 51 adults (80) completed six month study.
  • Atkins Diet (adlib) with initially lt25 g carbs
    Atkins MVI suppl. Carbs increased to 50 g if 40
    of wt loss achieved.
  • Average weight loss 10.3 5.9 plt0.001.
  • Average fat loss of 2.9 3.2 plt0.01
    (skinfolds).
  • Significant improvements in systolic and
    diastolic BP, total cholesterol, LDL,
    triglycerides and HDL.
  • Increases in urinary calcium and uric acid.

47
  • Westman EC, Yancy WS, Guyton JS. AHA. Nutrition
    Abstracts. Circulation (Supplement II).
    2002106(19).
  • Six month RCT comparing Atkins Diet (lt20 g/day
    Carbs) to Low Fat/Low Cal Diet (no composition
    given in abstract).
  • MVI, Borage, Flaxseed and Fish Oils supplements
    given to low carb group.
  • Mean BMI of 34.5 kg/m2 at baseline.
  • Low Carb Group, n 36 Low Fat Group n 27.
  • Greater weight loss in low carb group 13.8 to
    8.8.
  • Reduction in VLDL greater in low carb group.
  • Both groups had a 73 reduction in small LDL and
    an overall increase in LDL particle size.
  • The low carb group had a larger increase in large
    LDL particles.

48
Popular Weight Loss Diets Whats The Evidence?
Moderately High Protein Lower Carbohydrate (30
protein lt30 fat 40 carbohydrate) Dr Manny
Noakes Senior Research Dietitian CSIRO Clinical
Research Unit Australia
Health Sciences and Nutrition
49
Rationale for Moderately High Protein Intakes in
Weight Loss? Emerging scientific evidence for
effects on satiety Dietary pattern that is
nutritionally adequate
50
Emerging Scientific Evidence
  • Lean body mass spared - glucose tolerant women
  • (Piatti et al,1994)
  • Increased satiety - glucose tolerant women
  • (Latner Schwartz, 1999)
  • Thermic effects - obese, hyperinsulinaemic men
  • (Hwalla Baba et al,1999)
  • High protein/Low GI -25 decrease in ad libitum
    intake obese men
  • (Dumesnil et al 2001)
  • Thermic effect of HP meal 28 greater no change
    in REE - Type 2 diabetes (Luscombe et al 2002)
  • Endocrine and metabolic improvements - women
    with PCOS
  • (Moran et al 2003)

51
Zone vs Atkins vs Conventional
  • Mean weight loss was 5.1 kg for those who
    completed the 12-week program.
  • No significant differences in total weight, fat,
    or lean body mass loss by diet group.
  • 91 commenced study and 49 completed the 12 weeks.
    Attrition was substantial for all plans
  • Atkins 43,
  • Zone 60,
  • Conventional 36

Landers P J Okla State Med Assoc. 2002
52
Protein vs Carbohydrate in ad libitum Fat Reduced
Diet
  • Skov et al 1999
  • High-carbohydrate
  • (HC, protein 12 energy) n25
  • High-protein
  • (HP, protein 25 energy) n25
  • RESULTS AFTER 6 MONTHS
  • 5.1 kg in the HC group
  • 8.9 kg in the HP group (P lt 0.001)
  • More subjects lost gt 10 kg in the HP group (35
    vs 9).
  • HP diet decreased fasting plasma triglycerides
    significantly.

53
Increased Protein/Carb ratioin overweight women
CHO/protein ratio 3.5 (CHO Group) 68g
protein 1.4 (Protein group) 125g protein
Layman et al J Nutr. 2003
54
Increased Protein/Carb ratioin overweight women
CHO/protein ratio 3.5 (CHO Group) 68g
protein 1.4 (Protein group) 125g protein
Layman et al J Nutr. 2003
55
0 4 8
12
Weight Loss
Maintenance
HP


Weight Loss
Maintenance
LP

Interventions Fat lt30, sat fat lt10
6500kJ High Protein (HP) - 28 E Protein, 42 E
CHO Low Protein (LP) - 16 E Protein, 55 E
CHO

Parker B, Noakes M, Luscombe N, Clifton
P. Diabetes Care. 2002
56
Foods HP diet LP diet
Weetbix 1 1
Milk - 1 fat 250ml 250ml
Skim milk powder 30g -
Fruit Yoghurt - 0.1 fat 200g (7oz) -
Wholemeal bread 2 sl 3 sl
Fruit 2 small 3 small
Meat/fish/chicken 200g (7oz) 100g (3.5oz)
Low kJ Vegetables lt2.5 cups lt2.5 cups
Cheese - 3 fat 60g (2oz) -
Rice - 1 cup cooked
Canola lite margarine 2 tsp 3 tsp
Sunola oil 3 tsp 3 tsp
Shortbread biscuits 3 4
57
Dietary Protein Effects in Type 2 Diabetes
  • Total fat mass significantly decreased in women
    on HP diet (12.4)
  • Abdominal fat mass significantly decreased in
    women on HP diet (12)
  • Significant decrease in LDL cholesterol levels on
    HP diet (5.7)

Parker B, Noakes M, Luscombe N, Clifton
P. Diabetes Care. 2002
58
High Protein Diets and Renal Function in D2
  • Urinary albumin excretion was not affected by
    dietary protein during weight loss
  • n19 with microalbuminuria
  • HP diet 24.2 to 19.8 mg/l (n12)
  • LP diet 4.3 to 3.5 mg/l (n7)

Parker B, Noakes M, Luscombe N, Clifton
P. Diabetes Care. 2002
59
High Protein Diets InSubjects With High Insulin
Diet effect p lt 0.05
9.6
22.8
Farnsworth et al AJCN 2003
60
Insulin Response to Test Meals
Diet effect p lt 0.05
Farnsworth et al AJCN 2003
61
Glucose Response to Test Meals
Diet effect p 0.020
Farnsworth et al AJCN 2003
62
Aim
  • To compare a high protein weight loss diet with a
    high carbohydrate diet on
  • weight loss and body composition
  • nutrient status
  • bone turnover markers
  • measures of heart disease risk
  • in women over 12 weeks ..and subsequently
    follow up for 1 year
  • Diets
  • 1. High carbohydrate
  • 2. High protein, high red meat

63
High Meat Protein 5600 KJ (1330 kcal)
  • Cereal
  • Low fat milk (250ml) 8oz
  • Wholemeal bread (2 slices)
  • Fruit (2)
  • Beef/lamb 200g (7oz)-
  • dinner
  • Chicken/fish/meat 100g (3.5oz) lunch
  • Vegetables 2.5 cups
  • Diet Yoghurt 200g (7oz)
  • Canola oil 3 tsp
  • Wine 2 glasses/week (optional)

34 protein 20 fat 46 carbohydrate
109g protein 31g fat 161g carbohydrate
64

High Carbohydrate 5600 KJ (1330 kcal)
  • Cereal
  • SKIM milk (250ml) 8oz
  • Wholemeal bread (3 slices)
  • Fruit (3)
  • Chicken/pork/fish 80g - 3oz
  • Vegetables 2.5 cups
  • Canola oil 3 tsp
  • Pasta/rice 120g/4oz cooked
  • Low fat biscuits 3
  • Wine 2 glasses/week (optional)

17 protein 20 fat 64 carbohydrate
57g protein 31g fat 229 g carbohydrate
65
Baseline characteristics by TG Status
66
Weight Loss by Triglyceride Status
  • Sig diet effect
  • P0.023

High protein
High carb
67
Total And Midriff Fat Loss Dexa Data
Sig diet effect
High protein
High carb
68
Triglycerides by TG status
HIGH TG
Diet X TG interaction P0.01
?10
?28
LOW TG
69
(Effect of diet P0.07, with overall ANOVA
p0.019) after accounting for TG status
70
Significant effect of diet P0.005 suggesting
lower energy intake on high protein diet
71
Calcium Excretion
Calcium excretion decreased on both diets
reference range 2.5-7.5mmol/24hr
Calcium excretion mmol/24hr
week 0 week12
High protein
High carb
72
CONCLUSION
  • There is emerging evidence that moderately high
    protein lower carbohydrate diets for weight loss
    are advantageous to conventional high
    carbohydrate diets for
  • Women with high TG
  • Women with type 2 diabetes
  • Subjects with elevated insulin levels

There is no evidence that such moderate dietary
patterns pose any health risks although more
extended studies in overweight subjects with mild
renal impairment are necessary to confirm safety
in this group
73
Popular Weight Loss Diets Whats the Evidence?
Low-fat and Very Low-fat Diets
  • Keith-Thomas Ayoob, EdD, RD, FADA
  • Albert Einstein College of Medicine
  • July 17, 2003

74
Macronutrient distribution
  • American Heart Association-style
  • lt 30 fat
  • 15 protein
  • 55 CHO
  • Very low-fat diet
  • 10-15 fat
  • 12-15 protein
  • 72-75 CHO

75
Typical dinner--AHA-style
  • 3-oz. Broiled salmon
  • 2/3 cup rice
  • 1/2 cup mixed vegetables
  • 1 cup salad greens, 2 tsp. Vinaigrette
  • 1 slice whole wheat bread
  • 1 tsp. butter
  • 1/4 cantaloupe

76
Typical dinner--very low-fat
  • 3-oz. baked whitefish
  • 1-1/2 cups sauteed collard greens
  • baked sweet potato
  • 1/2 cup wild rice pilaf
  • baked apple

77
Low-fat Diets Weight Loss
  • 2003 review by Pirozzo, et al
  • Criteria for inclusion
  • Randomized Ccontrolled Trial (RCT) of
  • Low- Fat vs. other wt loss diets
  • primary purpose was wt. Loss
  • Age gt 18 years BMI gt 25 at baseline
  • Followed for at least 6 months
  • Low fat diet lt 30 of calories from fat

Pirozzo, S. et al. Cochrane Database of
Systematic Reviews. 1, 2003.
78
Low-fat Diets Weight Loss
  • Four 6-months studies
  • Five 12-month studies
  • Three 18-months studies
  • Result
  • No significant differences compared to other
    weight loss diets

79
Low-fat Diets Weight Loss
  • Meta-analysis of 34 studies,
  • 2-12 months duration
  • ad lib low-fat diets vs. controls
  • Result
  • 3.3 kg loss in low-fat groups (sig.)
  • Main factors
  • degree of dietary fat reduction
  • pre-treatment body weight

Astrup A, et al. Int J Obes Relat Met Dis. 2000
Dec 24(12)1545
80
Low-fat Diets Long-term Success
  • Review by Ayyad Anderson, 2000
  • Criteria for inclusion
  • adults
  • Follow up of gt 3 years
  • Follow up of gt 50 of original study group
  • Criteria for long-term success
  • Maintain gt 9-11 kg or all weight initially lost

Ayyad C and Anderson T. Obesity Reviews, 2000
1113-9
81
Low-fat Diets Long-term Success
  • Overall, 15 of followed-up subjects met criteria
    for success
  • Diet alone 15 met follow-up success
  • Diet group therapy 27 met success
  • Diet behavior mod. 14 met success
  • Active follow-up better than passive for long
    term success (19 vs. 10)

82
Low-fat diets vs. moderate/high-fat diets
  • 12 month duration
  • 4 DIETS
  • low-fat(LF)
  • moderate fat(MF)
  • mod fat-isocaloric(MF-iso)
  • high fat(HF)
  • weight, lipids, CV risk

Fleming, RM. Preventive Cardiology. 5(3)110, 2002
83
RESULTS Low-fat vs moderate high-fat diets
body weight lost at 12 months
NS
Wt loss associated with calories ONLY
84
Low-fat diets and satiety
  • Review of low-energy diets, glycemic index (GI),
    and obesity
  • Low-GI foods Increased satiety
  • low-fat, low-GI-based diets promote satiety and
    may therefore promote weight loss
  • high-GI diets weight gain and lower satiety
  • Similar in animal studies

Brand-Miller et al. Am J Clin Nutr. 76(1)281S,
2002 July
85
Long-term Compliance/Maintenance
  • McGuire et al
  • random digit phone survey
  • maintainers lost gt 10 of wt. , maintained for
    gt 1 yr.
  • 69 Maintainers, 56 regainers, 113 wt-stable
    controls

McGuire et al. Int J of Ob Rel Metab Disord
J of the Int Assoc Study of Ob. 23(12)1314,
1999 Dec
86
Long-term Compliance/Maintenance
  • Common factors for success
  • lower-fat intake than regainers/controls
  • behavior strategies used more than regainers
  • more physically active, esp. strenuous activity

87
National Weight Control Registry
  • Maintained a loss of gt 25 lb. for gt 1 year
  • lost weight by different methods
  • Maintainers
  • low fat, modest calorie intake
  • Physically active 4-5 days/week

88
LF Diets and Drop-outs
  • Problem in many studies
  • Most studies are 6 months or less
  • Only count those who completed study
  • Longer studies self-select
  • Several studies do show compliance after 1 year
  • Drop-out rate 11-40 (Pirozzi, et al)

89
Lipids low-fat diets
  • Low calorie AND low/moderate fat
  • significantly lower cholesterol, LDL-chol, TGs,
    TC/HDL ratios
  • Low-calorie, high-fat diets, OR mod fat,
    isocaloric diets
  • no significant changesTG, TC, HDL, LDL-chol

Fleming, RM. Preventive Cardiology. 5(3)110, 2002
90
C-reactive protein (CRP) low-fat diets
  • CRP strongly associated with BMI
  • LF diet (15 fat, 62 CHO) -- 12 wks
  • CRP significantly ? with Low-Fat/low- calorie
    diet and wt loss
  • Other dietary composition not investigated

Heilbron et al. Arterioscl, Thromb Vasc Biol.
21(6)968, 2001 June
91
LDL low-fat diets
  • 2001 review by Krauss
  • LDL-A desirable large, fluffy LDL
  • LDL-B small, dense LDL (atherogenic)
  • Conclusion
  • genes play a role
  • LDL-B benefits from a low-fat diet
  • LDL-A no benefits from low-fat diet IF
    isocaloric, may convert to LDL-B profile
  • CAVEAT studies are often short-term, not all
    hi-CHO diets are alike

Krauss. J of Nutr. 131(2) 340S 2001 Feb
92
HDL low-fat diets
  • Meta-analysis of studies gt 2months
  • LF diet lowered HDL, less so when fed ad lib than
    isoenergetically
  • Epi studies consistently show populations with LF
    diets and low-HDL have LOW atherosclerosis
  • Diets high in fruits, vegetables and grain fiber
    promote less atherosclerosis, cancer

Jequier E and Bray G. Am J of Med. 113(9) supp.
241 2002 Dec
93
Effect of type and amount of fat on HDL/lipids
  • Meta-analysis of 60 studies, Mensink et al
  • Conclusion
  • Replacing fat with CHO isoenergetically may
    increase total/HDL ratio
  • Replacing fat with CHO and reducing calories
    could have same effect as replacing SFA with MUFA
    and PUFA
  • Replacing trans-fat with MUFA/PUFA had best
    effect on blood lipids
  • Caveat Results are general but the need is
    individual

Mensink, RP et al. AM J Clin Nutr. 77(5) 1146,
2003 May
94
LF diets and insulin
  • Review by Brand-Miller, et al
  • Low-fat, hi-CHO, hi-GI diets may increase insulin
    response
  • BUT low-fat, low glycemic diets may promote wt
    loss via increased satiety, lowered insulin
    response
  • Exercise improves insulin response

Brand-Miller et al. Am J Clin Nutr. 76(1)281S,
2002 July
95
CONCLUSIONS
  • Calories count more than fat Low energy diets
    are more effective at producing weight loss than
    low-fat diets
  • BUT low-fat diets may make it easier to reduce
    total energy intake

96
CONCLUSIONS
  • Risks of Low-fat diets
  • Difficult long-term compliance on very low-fat
    diet
  • increases with close follow-up and group support
  • type of CHO may affect outcome, possibly by
    altering satiety
  • Benefits
  • Strong association with long-term maintenance
  • LF, hi-CHO, hi-fiber diet reduces other health
    risks and is usually rich in vitamins, minerals,
    and phytonutrients

97
UNANSWERED QUESTIONS
  • LONGER STUDIES NEEDED!
  • Do metabolic parameters show adaptation over
    time? Is long-term adaptation different?
  • Should physical activity and/or metabolic profile
    affect recommendation of diet type?
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