The Case for the High Fat, Low Carbohydrate Diet Eric C. Westman, M.D. M.H.S. Duke University Medical Center Durham, North Carolina Associate Professor of Medicine Course Director, Medical Management of Obesity Vice-president, American Society of Bariatric Physicians Fellow, The Obesity Society Consultant to Atkins Nutritionals, Inc. Co-author of The New Atkins for a New You
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The Case for the High Fat, Low Carbohydrate Diet
Eric C. Westman, M.D. M.H.S. Duke University Medical Center
Durham, North Carolina
Associate Professor of Medicine Course Director, Medical Management of Obesity
Vice-president, American Society of Bariatric Physicians Fellow, The Obesity Society
Consultant to Atkins Nutritionals, Inc. Co-author of The New Atkins for a New You
Assumptions About Diets
• Humans must eat 120 grams of carbohydrate daily • Low carb diets cannot lead to weight loss because
they don’t explicitly restrict calories • Low carb diets are “high protein” diets • LCKDs cause “harmful ketosis” • Low carb diets are “hard to maintain” • LCKDs diets increase cardiometabolic risk
Human Essential Nutrients • Water • Energy • Mineral elements
– Inositol, choline, carnitine Harper AE. Defining the essentiality of nutrients. In Shils ME et al, eds. Modern Nutrition in Health and Disease. Baltimore, William & Wilkins, 1999, pp 3-10.
Daily Carbohydrate Requirements
• “The lower limit of dietary carbohydrate compatible with life apparently is zero, provided that adequate amounts of protein and fat are consumed.”
• “The minimal amount of exogenous and endogenous carb is dependent upon the brain (100-140 g glucose/d).”
• After ketoadaptation, 80% of the CNS energy can be derived from ketones, leaving 20-28 g glucose/d.
• “Endogenous glucose production rate: 2-2.5 mg/kg/min ~ 2.8 – 3.6 g/kg/day. In a 70 kg man, this represents 210-270 g/day.”
Institute of Medicine, Dietary Reference Intakes, 2008
Food
Lipids Carbohydrates Proteins
Fatty acids + glycerol Amino acids
Acetyl coA
Pyruvate
Energy Processing With Carbohydrate
Food
Lipids Proteins
Fatty acids + glycerol Amino acids
Acetyl coA
Pyruvate
Energy Processing Without Carbohydrate
Effect of Very Low Carbohydrate Diets or Starvation on Carbohydrate Metabolism
Individuals choose foods that they like from a list of low glycemic foods.
Six-month Pilot Study: Diet Composition
Composition
Mean Daily Intake
% of Daily Caloric Intake
Protein 113.8 g 32.1
Fat 95.5 g 59.6
Carbohydrate 22.3 g 6.5
Calories 1427.3 kcal
Westman et al. Am J Med 2002;113:30-36.
LCKD vs. LFD Diet Composition
Diet Component Low Fat
(n=7) Low Carb
(n=13)
Protein 73g (18%) 109g (30%)
Fat 54g (31%) 98g (60%)
Carbohydrate 201g (51%) 35g (10%)
Energy 1588 kcal 1472 kcal
* Food records are from the entire 6 months
Low Carbohydrate Diet Composition
0
50
100
150
200
250
300
350
net carb fiber protein fat
gm/d
Usual Diet (3111 kcal/d)
Low Carb (2164 kcal/d)
Boden G et al. Effect of a low-carbohydrate diet on appetite, blood glucose levels, and insulin resistance in obese patients with type 2 diabetes. Ann Intern Med 2005;142:403-411.
Assumptions About Low Carbohydrate, High Fat Diets
• Humans must eat 120 grams of carbohydrate daily • Low carb diets cannot lead to weight loss because
they don’t explicitly restrict calories • Low carb diets are “high protein” diets • LCKDs cause “harmful ketosis” • Low carb diets are “hard to maintain” • LCKDs diets increase cardiometabolic risk
The Role of Ketones • Ketone bodies: molecules that deliver energy • Ketones can be used by all cells except
– Fed state 0.1 mmol/L – Overnight fast 0.3 mmol/L – Low-carb ketogenic diet 1–3 mmol/L – > 20 days fasting 10 mmol/L – Diabetic ketoacidosis 25 mmol/L
• Serum pH did not decrease below 7.37 in a study performing arterial blood gas analyses
Meckling KA, Can J Physiol Pharmacol, 2002; Coleman MD, J Am Diet Assoc, 2005; Yancy WS, Eur J Clin Nutr, 2007
Metabolism Society, Spring 2011 Conference on Ketone Bodies
• Review of Biochemistry of Ketone Bodies • Ketone Body Effects on Cardiac Energetics and Glycolytic
Flux • Ketone Bodies and Cancer • Human Keto-adaptation: Physiology and Function • Anti-ketogenic Effect of Insulin and Dietary Carbohydrate • Clinical Treatments using Nutritional Ketosis • The Ketogenic Diet for Epilepsy
Assumptions About Low Carbohydrate, High Fat Diets
• Humans must eat 120 grams of carbohydrate daily • Low carb diets cannot lead to weight loss because
they don’t explicitly restrict calories • Low carb diets are “high protein” diets • LCKDs cause “harmful ketosis” • Low carb diets are “hard to maintain” • LCKDs diets increase cardiometabolic risk
Low Carbohydrate Internet-based Support Group Survey
• Active Low-Carber Forum is an on-line support group started in 2000 and in 2008 had 86,000
• An anonymous 2-item survey was posted to describe the attitudes and behaviors of people following low carbohydrate diets
• Survey respondents (n=2000) were predominantly female, overweight, and following the Atkins diet or some variation of it
• Over 1400 claimed to have used a low carb diet to lose and maintain at least a 30 pound weight loss
• 28% of respondents reported that their doctor was initially neutral but supportive after favorable results were obtained
Feinman RD, Vernon M, Westman EC. Nutrition Journal 2006;5:26.
Low Carbohydrate Diet Are Very Popular in Sweden
(Google Searches for Popular Diets in Sweden 2008-present)
Low Carbohydrate High Fat Low Glycemic Index Weight Watchers
(Andreas Eenfeldt, www.kostdoktorn.se)
Assumptions About Low Carbohydrate, High Fat Diets
• Humans must eat 120 grams of carbohydrate daily • Low carb diets cannot lead to weight loss because
they don’t explicitly restrict calories • Low carb diets are “high protein” diets • LCKDs cause “harmful ketosis” • Low carb diets are “hard to maintain” • LCKDs diets increase cardiometabolic risk
Effect on Serum Lipids Variable Baseline Wk8 Wk16 Wk24 Change mg/dl mean mean mean mean Cholesterol 214 201 201 203 -6%* Triglycerides 130 82 75 74 -43%* LDL 136 136 128 126 -7%* HDL 52 49 58 62 +16%* Chol/HDL 4.3 4.3 3.6 3.4 -21%* Westman et al. Am J Med 2002;113:30-36.
Effects on Serum Lipids Low Fat (n=32) Low Carb (n=44)
Variable (mg/dl)
Week 0
Week 24 Change
Week 0
Week 24 Change
Cholesterol 233.8 220.7 -6%* 245.4 236.0 -4%
Triglyceride 184.0 144.4 -22%* 167.3 86.0 -49%*†
LDL-C 144.9 139.8 -4% 157.3 158.4 +1%
HDL-C 54.1 52.8 -2% 54.3 60.0 +11%*†
Chol/HDL 4.4 4.3 -5% 4.8 4.1 -15%*†
Trig/HDL 3.6 2.9 -18% 3.3 1.7 -49%†
* p < 0.01, for within-group changes from Baseline. † p < 0.05 for between-groups comparisons.
Outpatient LCKD RCTs: Weight Loss and Serum Lipids
* p<0.05 for between-groups comparison
2 months (“efficacy”)
Group n kcal/d CHO PRO FAT Weight LDL Trig HDL L/H
Atkins 40 1736 137g 93.5 89.5 -3.6 kg +1.3 -32.3 +3.2 -0.18 Zone 40 1434 157 90.4 54.5 -3.8 kg -9.7 -54.1 +1.8 -0.33 WWatchers 40 1615 191 80.5 54.5 -3.5 kg -12.1 -9.2 -0.2 -0.42 Ornish 40 1393 230 70.0 27.5 -3.6 kg -16.5 -0.4 -3.6 -0.21
Popular Diet Effects on Weight Loss and Cardiac Risk Factors
Dansinger ML et al. JAMA 2005;293:43-53.
12 months (“effectiveness”)
Group n kcal/d CHO PRO FAT Weight LDL Trig HDL L/H
Atkins 40 1886 190g 86.0 80.5 -2.1 kg -7.1 -1.2 +3.4 -0.39 Zone 40 1757 173 90.4 71.5 -3.2 kg -11.8 -2.5 +3.3 -0.52 WWatchers 40 1832 208 82.5 64.0 -3.0 kg -9.3 -12.7 -3.4 -0.55 Ornish 40 1819 218 76.5 64.0 -3.3 kg -12.6 +5.6 -0.5 -0.31
“To approximate the realistic long-term sustainability of each diet, we asked participants to follow their dietary assignment to the best of their ability to their 2 month assessment, after which time we encouraged them to follow their assigned diet according to their own self-determined interest level.”
2 months (“efficacy”)
Group n kcal/d CHO PRO FAT Weight LDL Trig HDL DBP
Atkins 77 1381 ~62g 97 84 -4.3 kg +2.3 -52.3 -0.4 -2.9 Zone 79 1455 152 87 57 -2.0 kg -5.3 -24.8 -0.5 -2.1 LEARN 79 1476 180 73 49 -2.8 kg -7.3 -17.2 -3.8 -1.4 Ornish 76 1408 220 60 33 -2.8 kg -10.1 -10.9 -5.3 -0.4
Popular Diet Effects on Weight Cardiac Risk Among Women
Gardner CD et al. JAMA 2007;297:969-977.
12 months (“effectiveness”)
Group n kcal/d CHO PRO FAT Weight LDL Trig HDL DBP
Atkins 77 1599 ~140g 84 78 -4.5 kg +0.8 -29.3 +4.9 -4.4 Zone 79 1594 179 80 62 -1.5 kg 0 -4.2 +2.2 -2.1 LEARN 79 1654 194 79 61 -2.5 kg +0.6 -14.6 -2.8 -2.2 Ornish 76 1505 195 68 50 -2.4 kg -3.8 -14.9 0 -0.7
“Each diet group attended 1-hour classes led by a registered dietician once per week for 8 weeks and covered approximately one eighth of their respective books per class...Efforts to maximize retention included email and telephone reminders…and incentive payments.”
Effect of Diet Programs on Metabolic Syndrome Parameters From Baseline to 12 Months
Atkins Zone LEARN Ornish P
(n=77) (n=79) (n=79) (n=76) value
BMI, kg/m2 -1.65 -0.53 -0.92 -0.77 .01
Waist-hip ratio -0.019 -0.013 -0.009 -0.012 .10
HDL-C, mg/dL +4.9 +2.2 +2.8 0.0 0.002
Triglycerides, mg/dL -29.3 -4.2 -14.6 -14.9 0.01
Non-HDL-C, mg/dL -5.1 -0.5 -4.0 -6.8 0.36
Insulin, µU/mL -1.8 -1.5 -1.8 -0.2 0.17
Glucose, mg/dL -1.8 -1.6 +0.5 -0.8 0.54
Diastolic b.p., mmHg -4.4 -2.1 -2.2 -0.7 0.009
Systolic b.p., mmHg -7.6 -3.3 -3.1 -1.9 <0.001
Gardner CD et al. JAMA 2007;297:969-977.
Re-examination of the A to Z Study [Gradner et al. JAMA 2007]
Women divided into tertiles based on insulin resistance
Weight loss at 12 mo:
Gardner, C.D., et al., Insulin Resistance - An Effect Moderator of Weight Loss Success on High vs. Low Carbohydrate Diets. Obesity, 2008. 16: p.
S82
Low Carb Low Fat
Insulin Resistant
Insulin Sensitive -11.7 lbs
-11.9 lbs -3.3 lbs
-9.0 lbs
Simply put, insulin resistance strongly influences how we respond to different diets
Validates the concept that insulin resistance is essentially an expression of carbohydrate intolerance
• Volek JS, Feinman RD. Carbohydrate restriction improves the features of Metabolic Syndrome: Metabolic syndrome may be defined by the response to carbohydrate restriction. Nutr Metab 2005;2:31.
• Feinman RD, Volek JS. Carbohydrate restriction as the default treatment for type 2 diabetes and metabolic syndrome. Scand Cardiovasc J 2008;42:256-63.
• Accurso A et al. Dietary carbohdyrate restriction in type 2 diabetes mellitus and metabolic syndrome: time for a critical appraisal. Nutr Metab 2008;5:9.
• Volek JS, Fernandez ML, Feinman RD, Phinney SD. Dietary carbohydrate restriction induces a unique metabolic state positively affecting atherogenic dyslipidemia, fatty acid partitioning, and metabolic syndrome. Prog Lipid Res 2008;47:307-18.
• Volek JS et al. Carbohydrate restriction has a more favorable impact on the metabolic syndrome than a low fat diet. Lipids 2009;44:297-309.
• Carbohydrate is not an essential nutrient • Low carb diets lead to weight loss because
abnormal hunger/appetite goes away • Low carb diets are adequate protein diets • Nutritional ketosis is a marker of burning fat • For many people low carb diets are easy to follow • LCKDs diets reduce cardiometabolic risk by
addressing the metabolic syndrome
Saturated Fat
Saturated Fat
Metabolic Processing of Saturated Fat
Saturated Fat Burned
as Fuel
Saturated Fat Burned
as Fuel
Low Carbohydrate
Diet (45 g CHO/d)
Low Fat Diet
(208 g CHO/d)
Saturated Fat Synthesis
Saturated Fat Intake
(12 g/d)
Saturated Fat Synthesis
Saturated Fat Intake
(36 g/d)
Forsythe et al. Lipids. 43(1):65-77, 2008
Does Insulin Reduction Explain the Lack of Rise in Serum Cholesterol?
Kennedy AR et al. A high fat, ketogenic diet induces a unique metabolic state in mice. Am J Physiol Endocrinol Metab 2007, February 13.
Diabetic Diet in the Pre-Insulin Era 1914-1921
“Quantity of food required by a severe diabetic patient weighing 60 kilograms”*
* Osler W, McCrae T. The Principles and Practice of Medicine. NY: Appleton and Co., 1923. Allen FM. Protein diets and undernutrition in treatment of diabetes. JAMA 1920;74:571-577. Newburgh LH, Marsh PL. The use of a high fat diet in the treatment of diabetes mellitus. Arch Int Med 1921;27:699-705.
Fat
Liver
Large LDL
Chylomicrons
Cells Atherosclerosis?
Thoracic Duct Superior Vena Cava
Triglycerides
Lymphatics
Triglyceride
Diet: Lipids
Observed Very Low Carb Diet
Fat
Small LDL
Carbohydrate
VLDL
Liver
LDL
Chylomicrons
Cells Atherosclerosis
Thoracic Duct Superior Vena Cava
Simple sugars Portal Vein
Triglyceride
Sugar
Triglycerides
Lymphatics
Triglyceride
Diet: Lipids
Observed Mixed Diet
LDL
Weight Loss, Improvements in Lipids
A 50 year old white female with obesity (BMI = 31.3) wants to lose weight.
Fasting lab tests:
Date BMI Wt (lbs) Chol Trig LDL HDL Glucose
6/10 31.3 178 245 247 141 54 92
Initiation of Carbohydrate Restricted Diet
8/10 29.1 164
2/11 24.5 141
5/11 23.5 138 209 46 119 81 88
She asks, “Why wasn’t I given this option before? I was just given the options of medications.”
Summary • Instructing people to limit carbohydrate grams leads
to a spontaneous reduction in caloric intake (without explicitly limiting calories) and: – Loss of body weight – Improvements in fasting serum lipid profiles (triglyceride,
HDL, chol/HDL ratio) – Improvement in systolic blood pressure – Reduction in waist circumference
• Low carbohydrate diets can be used in the clinical setting by trained practitioners
• A low carbohydrate diets is the preferred diet for metabolic syndrome
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