A higher protein diet consisting of 25-35% of calories from protein can help with weight management and maintaining lean mass compared to the standard 15-25% range. While protein needs vary, aiming for 1.5 grams of protein per kilogram of body weight is generally sufficient. For weight loss, choosing a higher protein option combined with low glycemic index carbohydrates provides the best results. Maintaining adequate iron levels is also important, especially for young women, as iron deficiency can cause fatigue and hinder exercise performance and diet compliance.

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Protein, Carbs & GI
What’s the Latest?
Dr Helen O’Connor APD1
Senior Lecturer Nutrition
University of Sydney
Overview
Scientific Evidence for Higher Protein Diets
› What is a higher protein diet?
› How much protein do we need?
› Weight management
- Lighter and leaner
- Metabolic health
- Nutrient density
- Appetite & eating behaviour
Carbs – The Good, The Bad & Secrets to Success
› Evidence for low GI carbs
› Secrets to Success
2
What is a Higher Protein Diet?
Nutrient Guidelines1 Paleo2 Hi-Protein3
Protein (%E) 15-25 34 25-35
Fat (%E) 20-35 21 10-30
Carb (%E) 45-65 45 35-65
3
1NHMRC; 2Eaton & Kroner 1985; 3Wycherley et al 2012
How Much Protein Do We Need?
› Evidence of a ‘set point’ requirement for protein
› Different requirement across species
› Eating continues until protein requirement is reached
› Known as ‘Protein Leverage Hypothesis’
Case Example
› Energy Needs 10,700 kJ/day
› Estimated protein requirement (1500 kJ/day)
› Remainder from carbs and fat (9,200 kJ/day)
› You keep eating until protein intake is satisfied
4
Excess CHO/Fat
consumed to meet
Protein target
Eaten quota of CHO + Fat but still
eating to get Protein requirement
Eaten quota of kJ but still short of protein
Protein Leverage Hypothesis
5
Range of possible diet rails to meet protein target
More energy consumed to
meet Protein target
Less energy
to meet protein
target
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High Protein Diets & Weight Loss
Wycherley et al 2012

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High Protein Diets & Fat Loss
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Wycherley et al 2012
High Protein Diets & Lean Mass
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Wycherley et al 2012
Case Study: Pete
9
› 52 yrs old, overweight
› Metabolic syndrome
› Office worker, gym 3/wk

Protein close to exercise is beneficial for hypertrophy in
young men
Cribb & Hayes Med Sci Sports Exerc 2006
Protein Window
Protein around
the time of
training
improves gains
in lean mass
Timing of Protein Intake
Cribb & Hayes Med Sci Sports Exerc 2006
Timing right also
translated into
improved
strength gains
Case Study: Samantha
12
› 21 y; few kg overweight
› Feels fatter than she really is
› Low iron & tired
› Training every day
› Frustrated with weight loss
Weight Gain in Young Women
› Moving away from home
› Busy with work and/or study
› Eating out and alcohol
› Limited shopping/cooking skills
› Budget constraints
› Decline in physical activity
› Cohabitation (friends or partner)
› Marriage & pregnancy
› Limited research on young women Ball et al 2002

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Weight Gain Greatest in Young Women
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http://www.alswh.org.au/
Young Women
(n=5770)
Mid-age Women
(n=8942)
Older Women
(n=6777)
649
(95% CI: 620-678)
492
(95% CI: 467-516)
162
(95% CI: 185-140)
Australian Longitudinal Study of Women’s Health
Weight Gain (g/year) 1996-2003
Popkin 2010 – review 1990-2000
Risks of Weight Gain in Young Women
› Weight Tracks Upward
- Negative physical & mental health
› Reproductive Health
- Infertility
- Obstetric complications
- Epigenetic effects for off spring
› Family & Future Health
- Women decide family meals
- Modelling health behaviour important
- Vicious cycle for future generations
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Macronutrients Study Diets & Exercise
Nutrient HP Diet HC Diet
Energy (kJ) 5615 5602
Protein (g) 107 (32% of E) 67 (20% of E)
Carbohydrate (g) 138 (41% of E) 191 (58% of E)
Sugars (g) 73 83
GI/GL 46/61 52/93
Dietary fibre (g) 23 24
Total fat (g) 38 (25% of E) 32 (21% of E)
Saturated fat (g) 11 10
Cholesterol (mg) 298 87
30 min accumulated physical activity daily (activity diary)
Weight Loss
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P=0.06
P=0.16
Iron Deficiency in Overweight/Obese
Young Women
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1. Ahmed et al 2008
2. Fayet & Samman 2007
4. Manuscript under review
Possibly
higher
prevalence in
younger
women?
Micronutrients - Study Diets
Nutrient EAR/AI HP Diet HC Diet
Thiamin (mg) 0.9 1.6 1.8
Riboflavin (mg) 0.9 2.5 2.5
Niacin Equiv (mg) 11 47 32
Vitamin C (mg) 30 156 160
Total Folate (µg) 320 332 355
Vitamin A Equiv (µg) 500 1058 1307
Sodium (mg) 460-920 2186 1940
Potassium (mg) 2800 3554 3096
Magnesium (mg) 255 318 268
Calcium (mg) 840 908 877
Phosphorus (mg) 580 1725 1282
Iron (mg) 8.0 12.2 9.9
Zinc (mg) 6.5 11.7 7.6
Red meat
4 times a
week only
nutrient
still short
(70%) of
the RDI.
More
Haeme
iron than
HC

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Nutrient Density of Higher Protein Diet
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Bioavailability is
Important
Iron Stores Maintained Better on HP Diet
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-­‐10
-­‐5
0
5
10
15
20
0
6
12
Ferri%n
(µgL-­‐1)
Time
(months)
Self esteem also increased more on HP diet
Too Tired to Lose Weight?
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Food, Mood & Mind Study
Hunger & Desire to Eat
22
0
1
2
3
4
5
6
Baseline 3
months 6
months 12
months
Hunger
VAS
Score
Higher
Protein
Diet
(n=21) Higher
Carbohydrate
Diet
(n=15)
p =0.525 p =0.070
p =0.227p =0.974
0
1
2
3
4
5
6
Baseline 3
months 6
months 12
months
Desire
to
Eat
VAS
Score
Higher
Protein
Diet
(n=21) Higher
Carbohydrate
Diet
(n=15)
p =0.316 p =0.059p =0.184
p =0.939
Repeated Measures ANOVA:
Diet: 0.184; Diet*Time: 0.229; Time: 0.459
Repeated Measures ANOVA:
Diet: 0.138; Diet*Time: 0.337; Time: 0.203
VAS: Hunger extremely hungry not at all hungry
Desire extremely strong not at all strong
Hunger & Desire to Eat Lower on HP Diet
Diogenes Weight Maintenance
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LP-HGI &
Control
Most Weight
Regain
HP or LGI
alone
moderate
benefit
0.93 kg less
gain in HP &
0.95 kg less
in low GI
HP-LGI
best
Larsen et al 2010
Case Study: Robyn
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• 36 y; training for a marathon
• Following paleo diet
• Tired & not getting results
Romjin et al 1984
Robyn is Training LOW
LOW carbs = SLOW times
Delayed Recovery
Robyn needs carbs to get
some quality ‘train high’

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Train Low in Well Trained
Yeo et al 2008; JAP 105 (5); 1462-1470
Low unable
to maintain
intensity
during HIIT
despite
financial
incentives
Marathon Des Sables -Toughest Footrace on Earth
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Paleo Runner: http://www.youtube.com/watch?v=2eFQs7bu-P8&noredirect=1
Stage Tom Wyles
(Paleo)
Mr Inexperienced#
(Carbs)
1 235 302*
2 185 47
3 207 40
4 99 36
5 62 28
Finish 118 46
* Finished 96th but incurred 1 h penalty for not filling out form correctly
after medical treatment for sore feet
#Mr Inexperienced advised by Dr Greg Cox Sports Dietitian AIS
Secrets to Success
› Fresh produce
› Varied diet (healthyeatingquiz.com.au)
› Higher protein, moderate carb intake
› Low GI carbs for health & weight loss
› Nutritional balance
› Iron is limiting nutrient – leads to tiredness
› Tired clients train poorly and lower diet compliance
› Top gear training needs ‘right carbs’
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‘When the training gets tough, the tough eat enough carbs’
Professor Louise Burke, AIS
Libby Trickett 2009
Olympian
Freestyle & Fly
Questions
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