Comparison of Medifast's 5 & 1 Plan to a Food-based Plan of Equal Calories

Inclusion Criteria: * Adult males and females (age between 18 and 65) * Obese (BMI \>=30.0 kg/m2 and \<50.0 kg/m2) * Non-smokers * No known food allergies to wheat, gluten, soy or nuts * \<14 alcoholic beverages per week * Willing and able to give informed consent * Not currently using appetite-affecting medications (e.g SSRIs, steroids, Ritalin) * Not pregnant or lactating * Primary care physician's permission for weight loss, normal labs and electrocardiogram (EKG) within past 1 year Exclusion Criteria: * Actively dieting * Eating Attitudes Test (EAT) \> 30 * Chronic uncontrolled health problems (not including obesity or diabetes) * Pacemaker or other internal electronic medical device * Schizophrenia, history of bipolar disorder, current Major Depressive Disorder * Dependence on alcohol or sedative-hypnotic drugs (e.g. benzodiazepines) * Cognitive impairment severe enough to preclude informed consent * Taking weight loss or appetite-suppressant medications * Taking appetite affecting medications (e.g. SSRIs, steroids, Ritalin) * Food allergies to wheat, gluten, soy, or nuts * Pregnant or lactating