High Quality Protein for Assisting With Weight Loss

The purpose of this study is to determine if, in presence of a reduced calorie diet, a breakfast containing high quality protein source (eggs) would be more effective in reducing hunger and increasing feeling of fullness compared to a breakfast containing a lower quality of protein, but equal energy density. A previous pilot study with the same endpoints yielded borderline significant results; this study has been powered based on that pilot to interrogate our hypotheses.

This will be a crossover study with 2 experiments. Subjects will follow a reduced energy weight loss diet of 1,200-1,500 kcal adjusted to each individual's body weight for totally 2 weeks in each experiment. They will come to the clinic from day 1 to day 7 and consume egg breakfast (EB) for 5 days under our supervision. Then on weekends during this period they will continue this breakfast at home based on our advice. The next week they will have cereal breakfast (CB) and the process is similar to that in the first week.

The 1st experiment will test the satiety from egg breakfast (EB) and following energy intake in both lunch and dinner, compared with CB (cereal breakfast). Lunch and dinner will be offered on 2 test days during each week. Anthropometric and body composition measurements, blood pressure, blood draw, satiety questionnaire, as well as energy intake will also be collected in the 2 test days and compared between 2 breakfast groups.

The 2nd one is to test whether EB will help in resisting the intake of foods considered tempting, but detrimental to weight loss efforts, compared with CB. The process is similar to experiment 1 except no blood draw, no dinner offered. Instead, a tempting food after lunch will be offered.

Eligibility Criteria:
Inclusion Criteria:

* Overweight and class I-II obese (BMI 25.0-39.9)
* Sedentary (\<3 hours/week of moderate intensity physical activity)
* Otherwise healthy

Exclusion Criteria:

* ≥5% body weight loss or gain in the three months preceding the study
* Post-menopausal (has not had period for 12 months)
* Plans to begin an exercise program or change current exercise routines between initiation of study and final study
* Anyone following a medical diet prescription
* Anyone with a chronic disease including type II diabetes, hypothyroidism, hypoparathyroidism, cardiovascular disease, cancer of any type
* Health conditions and chronic illness that contraindicate behavioral weight loss treatment using a low calorie diet: Unstable cardiac condition; Polycystic ovary syndrome; Prader-Willi syndrome; Major systemic illness; History of recreational drug abuse or eating disorder (Binge Eating Disorder); Familial hyperlipidemia; Major endocrine diseases (Cushing's syndrome, Grave's disease, Hashimoto's thyroiditis); Gastrointestinal disorder
* Anyone who is currently pregnant, or lactating
* Medications that may influence or inhibit appetite, sensory functioning, or hormone signaling
* Plans to begin taking any supplements that may influence weight loss
* Report of medical condition or surgical intervention that affects swallowing or chewing ability
* Anyone with a pacemaker or other internal medical device
* Any practicing vegans or vegetarians
* Any practicing gluten-free diet
* Allergy, aversion, or dislike to any of the foods offered for meals