Hyperprotein Diets

Dr. Clarence P. DavisBergstrasse 8

CH-8702 Zollikon

Dr. C.P. Davis

Subjects

General remarks on Obesity an associated riscs

Role of Protein in the Diet Definition of high Protein Diets High Protein Diets and Weight

Reduction– Atkins, Zone, Protein Power, Sugar

Busters, Stillman

Dr. C.P. Davis

19961991

Obesity Trends* Among U.S. AdultsBRFSS, 1991, 1996, 2004

(BMI 30)

No Data <10% 10%–14% 15%–19% 20%–24% ≥25%

2004

Source: Centers for Disease Control and Prevention

Dr. C.P. Davis

Obesity in EuropeSource: IOTF

YugoslaviaGreece

RomaniaCzech Rep.

EnglandFinland

GermanyScotlandSlovakiaPortugal

SpainDenmarkBelgiumSwedenFrance

ItalyNetherlands

NorwayHungary

Switzerland

30 4030040 20 10 10 20

women men

% BMI 30

Dr. C.P. Davis

Consequences of Obesity cardiovascular diseases

gallbladder disease

hormonal imbalances

hyperuricemia and gout

diabetes

cancer- breast- uterus- gallbladder- kidney- colon

gastro esophageal reflux

osteoarthritis

Dr. C.P. Davis

Risks associated with ObesityClassification

BMI kg/m2

Risk for concomitant disease*

waist circumference<102 cm (men) >102 cm (men) <88 cm (women)>88 cm (women)

Underweight <18.5Normal weight 18.5 – 24.9Overweight 25.0 – 29.9 increased high

Obesity Grade I 30.0 – 34.9 high strongly increased

Obesity Grade II 35.0 – 39.9 strongly increased

strongly increased

Obesity Grade III >40.0 very high very high*related to normal weight and normal waist circumference, risk for type 2 diabetes, hypertension, CHD.NIH/NHLBI The Practical Guide, Identification, Evaluation and Treatment of Overweight and Obesity in Adults, October 2000.

Dr. C.P. Davis

Obesity and heart failure: cumulative incidence in women

Kenchaiah S et al N Engl J Med. 2002 Aug 1;347(5):305-13

BMI 18.5-24.9kg/m2

BMI 25.0-29.9kg/m2

BMI >30 kg/m2

Dr. C.P. Davis

Obesity and heart failure: cumulative incidence in men

Kenchaiah S et al N Engl J Med. 2002 Aug 1;347(5):305-13

BMI 18.5-24.9kg/m2

BMI 25.0-29.9kg/m2

BMI >30 kg/m2

Dr. C.P. Davis

BMI and age related mortality

after Waaler HT Acta Med Scand Suppl. 1984;679:1-56

Rel

ativ

e ris

k

women

BMI (kg/m2)21

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

25 29 33 37 41

men age50-5455-5960-64

BMI (kg/m2)21

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

25 29 33 37 41

Dr. C.P. Davis

The diet generation ~ 30% of all male and ~ 45% of all

female US citizens are trying to lose weight

Diet books available on Amazon.com: ~ 38’000

Many of these books promote some sort of CHO restriction and hyperprotein diet– Dr. Atkins’ New Diet Revolution, The

Carbohydrate Addict’s Diet, Protein Power, Lauri’s Low-Carb Cookbook

Dr. C.P. Davis

Important Questions What is really known about CHO

restriction? Is the information scientifically sound?

What is the effect on composition of– weight loss (fat vs. LBM)– micronutrient status (vitamins and

minerals)– metabolic parameters (blood glucose,

insulin sensitivity, blood pressure, lipid levels, uric acid, ketone bodies)?

Dr. C.P. Davis

Role of Protein in the Diet Proteins are essential components of the

body and are required for the body’s structure and proper function– Enzymes, hormones, antibodies, transport and

structural components The nutritional quality of food proteins

varies and depends on essential amino acid composition (egg white = biological value of 100)

Foods with high protein quality are from animal source– eggs, milk, meat, poultry, fish

Dr. C.P. Davis

Role of Protein in the Diet In the US an average of 102 g of protein per

person per day is available in the food supply– Actual protein consumption ranges from 88 to 92

g for men and 63 to 66 g for women (12-15 % of total daily energy uptake)

Animal products provide ~ 75% of the essential amino acids in the food supply, followed by dairy products, cereal products, eggs, legumes, fruits, and vegetables

The RDA for protein of high biological value for adults is ~ 0.8 g/kg BW (~ 8-10% of total daily energy uptake)

Dr. C.P. Davis

Definition of high protein diets

High protein diets: >20% of total energy

Very high protein diets: >30% of total energy

Dr. C.P. Davis

Protein Intake at Various Levels of Energy Intake

Energy Intake, kcal/d

LPD(<10% cal)

AD(~15% kcal)

HPD(>20% kcal)

VHPD(>30% kcal)

1200 30 45 60 90

2000 50 75 100 150

3000 75 112 150 225

Protein intake is in grams per day.

St. Jeor ST, Ashley JM. In: Obesity: Impact on Cardiovascular Disease. 1999:233-246.

Dr. C.P. Davis

Compensatory Changes in the Macronutrient Composition of Various

Diets

Diet DescriptionFat(% kcal)

CHO(% kcal)

Protein(% kcal)

Alcohol(% kcal)

Average diet 34 49 14 3Moderate-fat diet 30 55 15 ...Very-low-fat/very-high-CHO diet

15 70 15 ...

Low-CHO/very-high-protein diet

30 40 30 ...

Very-low-CHO/very-high-protein/fat diet

55 15 30 ...

Dr. C.P. Davis

Some popular Diets Atkins

– Eating too many CHO causes obesity and other health problems; ketosis leads to decreased hunger

– Meat, fish, poultry, eggs, cheese, low-CHO vegetables, butter, oil; no alcohol

– Protein: 27%, CHO: 5%, Fat: 68% (saturated 26%)

– No long term validated studies published– Initial weight loss mostly water. Difficult to

maintain long-term because diet restricts food choices

Dr. C.P. Davis

Some popular Diets Zone (Montignac)

– Eating the right combination of foods leads to metabolic state at which body functions at peak performance, leading to decreased hunger, weight loss, and increased energy

– Protein, fat, CHO must be eaten in exact proportions (40/30/30). Low-glycemic-index foods, alcohol in moderation

– Protein: 34%, CHO: 36%, Fat: 29% (saturated 9%), Alcohol: 1%

– No long term validated studies published. Theories highly questionable.

– Weight loss based on caloric restriction. Could result in weight maintenance if carefully followed. Diet rigid and difficult to maintain.

Dr. C.P. Davis

Some popular Diets Protein Power

– Eating CHO releases insulin in large quantities, which contributes to obesity and other health problems

– Meat, fish, poultry, eggs, cheese, low-CHO vegetables, butter, oil, salad dressings, alcohol in moderation

– Protein: 26%, CHO: 16%, Fat: 54% (saturated 18%), Alcohol: 4%

– No long term validated studies published – Weight loss based on caloric restriction.

Limited food choices not practical for long term.

Dr. C.P. Davis

Some popular Diets Stillman

– High-protein foods burn body fat. If CHO are consumed, the body stores fat instead of burning it

– Lean meats, skinless poultry, lean fish and seafood, eggs, cottage cheese, skim-milk products; no alcohol

– Protein: 64%, CHO: 3%, Fat: 33% (saturated 13%)

– No long term validated studies published – Initial weight loss mostly water.

Maintenance based on strict caloric counting. Very limited food choices not practical for long term.

Dr. C.P. Davis

Comparison of various diets with regard to Body Fat, Body Protein and Body

Water

37

20

43

16

21

63

11

23

66

3

18

79

4

21

75

11

22

67

25

19

56

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

TF MF 1 MF 2 MF 3 MF 4 BN 1 SK 1

TF = total fasting; MF = Modifast, BN = formula with inferior protiens; SK = Schrotkur

Loss of body fat, body protein and body water with differend diets

The best results were

achieved with a

combination of 50 g of

proteins, 25 g CHO, and 10 g of fat

Wechsler JG et al. Fortschr Med. 1984 Jun 28;102(24):666-8

Dr. C.P. Davis

Effects of HPD Skov et al. Int J Obes Relat Metab

Disord. 1999; 23:528-536– 65 healthy overweight men and women– 2 ad lib fat reduced (< 30% kcal) diets

varying in protein content (12% vs 25% of kcal) over 6 months

– Larger weight loss with higher-protein diet (8.9 kg) vs lower-protein diet (5.1 kg)

– Larger fat loss with higher-protein diet (7.6 kg) vs lower-protein diet (4.3 kg)

Dr. C.P. Davis

Effects of HPD

On average, consumption of HPD and/or low-CHO diets resulted in 12-wk and 24-wk weight losses that were 2.5 ± 1.8 and 4.0 ± 0.4 kg greater, respectively, than those from consumption of the high CHO and/or low-fat control diets.– This implies a 233 kcal/day difference in

energy balance

Dr. C.P. Davis

Effects of HPD

Two possible hypotheses for difference in energy balance– 1) a low-CHO diet may increase energy

expenditure– 2) an increase in protein in the diet may

increase energy expenditure

Dr. C.P. Davis

Do Proteins increase Energy Expenditure?

Mikkelsen et al. Am J Clin Nutr. 2000; 72:1135:1141– Ad lib diet– Increase of protein from 11% to 28/29%– No change in fat (29%)– Reduction of CHO from 60% to 42/43%– Increase in energy expenditure by about

60 – 120 kcal/24 hour, depending on whether the protein was of plant or animal origin

Dr. C.P. Davis

Do Proteins increase Energy Expenditure?

Whitehead JM et al. Int J Obes Relat Metab Disord. 1996; 20:727-732– 50% energy restricted diet– Increase of protein from 15 – 36%– Compared with the weight-maintenance control

diet both diets resulted in a reduction of 24-hour energy expenditure

– Smaller reduction for higher-PD by 71 kcal/d compared with the lower-PD Lesser decrease of resting metabolic rate Lesser decrease of thermic effect of food

Dr. C.P. Davis

Do Proteins increase Energy Expenditure?

Not sure Small results cannot explain the effect

of the average 2.5 kg greater weight loss reported from low-CHO diets

Dr. C.P. Davis

Reasons for higher Weight loss with HPD

Dietary compliance– Difficult to document– Some evidence from comparative studies

with low-fat diets vs. low-CHO/HPD and theoretical weight loss

– Possible higher satiating effect of proteins

Dr. C.P. Davis

Dansinger ML et al. JAMA. 2005 Jan 5;293(1):43-53

Comparison of different diets with respect to compliance

Mean Self-reported Dietary Adherence Scores of All 4 Diet Groups, According to Study Month

Calorie-restriction

CHO-restriction

Glucose-restriction

Fat-restriction

Dr. C.P. Davis

One-Year Changes in Body Weight as a Function of Diet Group and Dietary Adherence Level for All Study Participants

Dansinger ML et al. JAMA. 2005 Jan 5;293(1):43-53

Comparison of different diets with respect to weight loss

Dr. C.P. Davis

Reasons for higher Weight loss with HPD

Limitation of food choices associated with low-CHO diets

Low-CHO diets induce small losses of body water (~ 1.5-2 kg)– Does not explain the difference generally

reported for comparisons of low-CHO and low-fat diets 1.9 kg is lesser than reported Greater weight loss is reported to be based on

fat loss not water

Dr. C.P. Davis

Limitations of current studies and outlook

Very few “pure” studies on HPD– Impossibility of manipulating one

macronutrient without changes in at least one other macronutrient

Studies on energy expenditure may not give the right picture– Too short time frame

Weight losses found in 12 weeks may not be representative of long-term effect

Dr. C.P. DavisFoster GD et al. N Enlg J Med 2003 22;348(21):2082-90

Comparison of Weight Loss

Dr. C.P. DavisFoster GD et al. N Enlg J Med 2003 22;348(21):2082-90

Urinary Ketosis

Dr. C.P. Davis

Limitations of current studies and outlook

Usually studies investigate only one side of the energy balance equation

Health issues are rarely investigated– The amount of protein recommended in

HPD exceeds established requirement and may impose significant health risks

– Little cross-sectional and longitudinal studies provide data on health effects of HPD

Dr. C.P. Davis

Risks associated with HPD Animal protein, saturated fat, and cholesterol raises

LDL-cholesterol HPD increase purine levels

– gout HPD increase urinary calcium loss

– osteoporosis Deficiencies in essential vitamins, minerals, and

fibers Increased cancer risk

– low phytochemical) VHPD with excessive limitations of CHO may lead to

loss of lean muscle tissue (glyconeogenesis)Larosa JC et al. J Am Diet Assoc 1980; 77:264-270Franzese TA. In: Kause‘s Food, Nutrition, & Diet Therapy. 2000:970-986Barzel US et al. J Nutr 1998; 128:1051-1053Costill DL et al. Sports Med 1992; 13:86-92

Dr. C.P. Davis

High-protein Diets and Weight Reduction

Weight reduction is achieved if there is an energy deficit (energy uptake < energy expenditure)

In obese individuals, macronutrient composition has little effect on the rate or magnitude of weight loss unless nutrient composition influences caloric intake

Overall caloric intake depends on palatability and satiety

Proteins are easily available, palatable and of high essentiality

Dr. C.P. Davis

High-protein Diets and Weight Reduction

High-protein diets are initially attractive– quick weight loss due to low CHO intake,

glycogen depletion, and ketosis High-protein diets usually induce

metabolic ketosis Ketosis may lead to lower caloric

intake VHPD may promote negative energy

balance due to significant food restrictions

Dr. C.P. Davis

High-protein Diets and Weight Reduction

The structured eating plan, strict eating schedules, and limited tolerance for high-protein foods reduce overall flexibility but offer initial appeal. These characteristics may help limit caloric intake and may account for weight loss. However, neither the efficacy of these diets compared with higher COH diets in promoting weight loss nor the safety of these diets has been documented in long-term studies.

St. Jeor ST et al. Circulation 2001; 104; 1869-1874

Dr. C.P. Davis

General Recommendation for HPD

The current evidence, combined with the need to meet all nutrient requirements, suggests that weight-loss diets should be moderate in CHO, moderate in fat, and that protein should possibly contribute one fourth to one third of energy intake.