Trial Information

The Impact of Higher Dairy and Dietary Protein on the "Quality" of Hypoenergetic diet-and Exercise-induced Weight Loss in Pre-menopausal, Overweight and Obese Young Women

Overweight to obese female subjects, who are habitually low dairy consumers and between the
ages of 19-45 years will be recruited from the McMaster University student and staff
population and from the surrounding Hamilton area. At study entry, all subjects will be
asked to complete a standard screening questionnaire to document their medical history,
current medication use, physical activity level, smoking habits, and alcohol consumption.
Subjects will also complete a calcium food frequency questionnaire. Before randomization and
study commencement, baseline measures will be done. These include: anthropometrics, fasting
blood samples, fasting urine sample, resting energy expenditure measures (REE), muscle and
adipose biopsies, cardiovascular measures (blood pressure, heart rate, blood vessel
stiffness and arterial elasticity) body composition (dual-energy x-ray absorptiometry
[DXA]), and a 7-day baseline food record analysis. Also, subjects' strength and fitness will
be assessed (1 repetition maximum (RM) and submaximal Astrand Test evaluations). During the
study, fasting blood samples will also be taken at weeks 4, 8, 12 and 16, DXA will also be
done at weeks 8 and 16, validated Body Image questionnaires will be filled out again t weeks
8 and 16, and body weight will be recorded every week. All other measures will be repeated
after 16 weeks (1RM, Astrand Test, biopsies, cardiovascular measures, REE). Magnetic
Resonance Imaging (MRI) will be carried out on a smaller portion of subjects on a voluntary
basis at weeks 0 and 16. Apon completion of the baseline testing, subjects will be randomly
assigned to one of the three intervention groups.

Part of the intervention will be in the form of 2 daily chocolate drinks (a post-exercise
drink plus one extra drink per day). Drink composition will differ depending on which group
subjects are randomized to. Drinks will be made to look and taste similar. In terms of the
daily diets, the DairyPro (middle/second) group will employ the same macronutrient
distribution as the Control (first) group but half the protein will be derived from dairy
sources, with subjects being asked to consume, on top of their supplemental chocolate drink,
2 yogurts (100 g each). In the control group, protein will be derived from sources other
than dairy. In the HiDairyPro (third) group, dietary protein will be manipulated so as to
comprise twice as much dietary energy versus the other two groups (i.e., 30% of energy
intake versus 15%). Protein (half of their daily requirement) will be derived from dairy
protein by asking subjects to consume, on top of their supplemental chocolate drink, 1
serving (250 ml) of 1% regular milk, 4 yogurts (100 g each) and 2 pieces of cheese (21 g
each).

Overview of supplemental drink composition and diet composition by group:

1. Control (Con) - a group consuming twice daily drinks containing no dairy protein or
calcium. Daily protein (15% total kcals) should be from non-dairy sources (i.e. meat,
egg, fish, chicken, lentils, beans, wheat gluten).

2. Dairy Protein Group (DairyPro) - a group consuming twice daily drinks containing 1%
chocolate milk and at least half of their daily protein (15% total kcals) intake from
dairy sources.

3. High Dairy Protein Group (HiDairyPro) - a group consuming twice daily drinks containing
1% artificially sweetened chocolate milk along with a diet formulated to contain 30%
(as opposed to only 15% in the Con and DairyPro groups) of their dietary energy from
protein with at least half of that coming from dairy protein.

Subjects will meet with a study dietitian/nutritionist at the beginning and biweekly
throughout the 16 weeks, and be provided with individual dietary counseling to reduce daily
calories by 500 kcal/d. Subjects will be provided with template diet records, nutrition
information sheets and macronutrient specific exchange lists to help with dietary compliance
and to promote healthy food choices. The weight-reducing diets will have macronutrient and
micronutrient profiles that are in accordance with the dietary regulations set forth by
Canada's Food Guide and the dietary reference intakes (DRIs). The macronutrient profile of
the 2 moderate protein groups (control and DairyPro) will be 15:30:55 (PRO:Fat:CHO), whereas
the subjects in the High dairy protein group (HiDairyPro) will consume a profile of 30:30:40
(15% substitution of carbohydrate for protein). Subjects will consume all other food (aside
from their designated drinks) in any manner they choose in accordance with the macronutrient
profile of their respective randomization allocations. Adherence to the prescribed diet will
be via collection of assigned biweekly food records, frequent contact with subjects, and
regular dietary counseling sessions.

In addition, all subjects will be given a custom exercise prescription consisting of
supervised resistance exercise and aerobic exercise. Intensity and duration of all exercise
sessions will be monitored and energy expenditure quantified using portable, validated units
that integrate accelerometry, heat flux and skin temperature. Exercise will take place in a
supervised setting at McMaster University. Subjects will perform exercise 7d/wk and will
exercise supervised 5d/wk (Mon - Fri). Resistance training sessions will take place 2x/week.
During these sessions, subjects will engage in a circuit weightlifting routine using guided
motion machines.