The Role of Dairy Foods in Fat Loss and Weight Loss in

Overweight and Obese Adults

Who is conducting this study?

            This study is led by Marta Van Loan, PhD, and colleagues at the USDA, ARS, Western Human Nutrition Research Center (WHNRC). The funding for this study comes from USDA, ARS, WHNRC and the National Dairy Council. This study has been reviewed and approved by the UC Davis Committee for the Protection of Human Subjects.

What is the purpose of the study?

            We hope to learn how dairy foods and diets with moderate calorie restriction are related to central body fat, body weight and body fat, blood pressure, hormones, blood triglycerides, cholesterol and fat cells.  We will also examine how diets with moderate calorie restriction and dairy foods affect your metabolic rate.

Who can participate?

            Eighty-four overweight and obese men and women, ages 20 - 45 years, who are generally healthy will be enrolled in the study. Volunteers are about 45 – 80 lbs. overweight (women), 30 – 60 lbs. overweight (men). We are looking for volunteers interested in losing weight by eating a moderate calories restricted diet for 12 weeks, but not currently trying to lose weight with diet, exercise or medications.

We need volunteers who are willing and able to eat 3 meals a day plus beverages and snacks provided to them and who can commit to the study schedule for fifteen consecutive weeks (105 days).

Who is NOT eligible to participate?

• Individuals who are vegetarians or cannot eat the meals provided
• Individuals currently taking calcium supplements or allergic to dairy products
• Individuals currently consuming more than 1 cup of milk or yogurt a day
• Individuals who smoke or use tobacco products
• Individuals taking prescription or over-the-counter medications for the purpose of weight loss, cholesterol lowering, anti-inflammatory medications, steroids, or thyroid-regulating medication
• Women who are pregnant, lactating, or planning a pregnancy

What do I need to do to participate?

            Volunteers will complete a health-screening visit at WHNRC, West Health Sciences Drive on the UC Davis campus, including questionnaires, height, weight, vital signs and a blood draw. This one-hour visit will take place in the morning following an overnight fast of 12 hours.

If you are selected for the study, you will agree to eat a prepared diet, consisting of 3 meals plus one snack per day, seven days a week for a period of fifteen consecutive weeks (105 days). You will be required to eat all of the food provided and only the foods provided to you by the study. The diet consists of typical foods in a 7-day rotating menu. You will come to the WHNRC to be weighed and to receive meals. The eating schedule is as follows: beginning on study week 1 through week 5 you will be asked to eat 10 of the 21 meals in each week on-site. (For example, Breakfast and Dinner could be eaten onsite, with Lunch and weekends packed “to-go”.) Meal times at the facility are: Breakfast (7:30a.m.-9:00a.m.), Lunch (12:00-1:30p.m.) and Dinner (5:00p.m.-6:30p.m). During study weeks 6-12 your food will be packed “to-go” and you will come to our facility to pick your groceries once a week. On study weeks 13-15 you will resume eating 10 of your 21 meals in each week at the WHNRC Building on the UC Davis campus.

 For the first 3 weeks of the study you will be given enough calories, based on your gender, age, and activity level, to maintain your weight. The remaining 12 weeks of the study you will be randomly assigned to one of two calorie restricted diets with varying dairy servings. You will be instructed not to change your activity level or lifestyle during the course of the study (15 weeks). The diets provide sufficient amounts of vitamins and minerals required for adults. You will not be allowed to consume additional vitamins, minerals or herbal supplements. You will be allowed to consume one cup of black coffee per day, and sugar-free, caffeine-free beverages (provided at no cost to you). You will not be allowed any other caffeinated beverages. The standard diet will contain approximately 35% of calories from fat, 16% calories from protein, 49% calories from carbohydrate, and about 14 g fiber, which is typical of an average American diet.

            During weeks 1-3 you will eat the standard diet described above at a calorie maintenance level. Then, you will be randomly assigned (by flipping a coin) to either Diet A or Diet B for 12 weeks. One diet has one serving of dairy; the other has 3 servings a day. During the first three weeks, you will have your body weight measured every day. The remaining twelve weeks, you will have your body weight, vital signs and body temperature measured once per week. There are three study time points (wk 3, 14, 15) in which you will have blood draws done, as well as RMR’s, appetite assessment, and blood pressure measured. Each study time point (wk 3, 14, 15) requires you to spend two (2) full days (~7:00a.m.-8:00p.m.) at the WHNRC facility.

            You will have a CT (Computed Tomography) scan, DEXA (Dual Energy X-ray Absorptiometry), and a fat biopsy at two study time points (wk 3 and wk 15). These are standard procedures that have been used in many research studies to assess body fat composition, fat cell number and fat cell size. The amount of radiation exposure would be comparable to that of a cross-country airplane trip.

Here is an overview of the study:

Wk1

Wk2

Wk3

Wk4

Wk5

Wk6

Wk7

Wk8

Wk9

Wk10

Wk11

Wk12

WK13

WK14

Wk15

WT

WT

WT

WT

WT

WT

WT

WT

WT

WT

WT

WT

WT

WT

WT

Physical Activity

RMR

RMR

Physical Activity

RMR

Physical Activity

Physical Activity

RMR

RMR

Body Comp

Body Comp

Fat biopsy

Fat biopsy

Appetite

Appetite

Appetite

BP

BP

BP

CT scan

CT scan

12-hr blood

12-hr blood

12-hr blood

What are the benefits to you from this study?

• You will receive all of your food for fifteen weeks (105 days) at no cost. For 12 weeks of the study, you will be provided a moderate calorie-restricted diet for the purpose of weight loss under the supervision of a Registered Dietitian.
• You will receive an evaluation of your health status at no cost.
• You will learn about the science of nutrition and play an important role in research, which may discover beneficial health effects of dairy.
• If you are enrolled in the study, you will be paid $10 physical activity and appetite assessment; $15 blood draw; $30 resting metabolic rate; $40 CT scan; $40 DXA; $40 adipose tissue biopsy; $75 for test meal and endocrine hormone procedure for a total of $500.

What should I do if I have more questions?

Call 530-752-5177 and press 5 to leave a message or visit our website at www.ars.usda.gov/pwa/davis/whnrc. Someone from the study will get back to you.