This pilot study is an active control randomized controlled trial with a sample size of 30 that will consist of 2 groups, to evaluate the effects of a one-month alternate day intermittent energy restriction (AltER) intervention on body weight, body composition, resting metabolic rate in college students with obesity as compared to a standard reduced calorie diet (RCD). Among the 30 participants, 15 will be randomized into the experimental group that will receive the AltER intervention while the other 15 will be a part of the active control group that will follow a RCD. The study will be conducted at the Texas Tech University Nutrition and Metabolic Health Initiative.

This pilot study proposes to investigate the scope and benefits of a novel, hybrid alternate day fasting protocol tailored to the college student lifestyle. This protocol - Alternate Day Intermittent Energy Restriction (AltER) is novel because it proposes to modify the standard ADF regime by increasing energy intake to 40% of calorie needs on fasting days. While this may not be as restrictive as other protocols, it still can help create a significant energy deficit. Additionally, it will provide flexibility by allowing for two consecutive fast days if the individual chooses to. While most dietary interventions can achieve significant weight loss in this short duration we expect that this approach tailored to college lifestyle will be superior to typical dietary restriction.

Subjects will be asked to attend two approximately 90-minute assessment visits (4 weeks apart) at the NMHI facility They will have their height weight and blood pressure measured, fill out questionnaires (attached), and have body composition (BodPod) and resting metabolic rate (Metabolic Cart) measured.

At completion of visit one they are randomly assigned to one of two Diet protocols designed to reduce calories and help them to safely lose weight They will also be asked to respond to a brief (3 questions) email survey weekly.

The AltER diet alternate between full calorie (no restriction) eating days with eating 40% of your daily caloric requirement on the other day. There will be occasional exceptions allowed with maximum of two 40% days in a row (followed by two full days) based on personal schedule with prior PI approval. The RCD will require a reduction of 500-1000 calories below daily energy requirement. The intervention or control diet will be followed for a duration of 4 weeks at the end of which the participants will come in for visit 2 which will follow a similar format like visit 1.

General Aim

To determine the effect of a novel, alternate day intermittent calorie restriction intervention on body weight, fat mass and resting metabolic rate of college students with obesity as compared to a standard reduced calorie diet 3.2.1. Specific Aim 1: To determine the effect of a novel, alternate day intermittent calorie restriction intervention on body weight of college students with obesity as compared to a standard reduced calorie diet.

3.2.1. Specific Aim 2: To determine the effect of a novel, alternate day intermittent calorie restriction intervention on fat mass of college students with obesity as compared to a standard reduced calorie diet.

3.2.2. Specific Aim 3: To determine the effect of a novel, alternate day intermittent calorie restriction intervention on resting metabolic rate of college students with obesity as compared to a standard reduced calorie diet.

3.2.2. Specific Aim 4: To explore the relationships of stress, sleep physical activity and weight history/demographic variables in relation to primary outcomes of interest.

Inclusion Criteria:

1. Age: 18 -25 years
2. Enrolled as full-time college students
3. Have a BMI ≥ 30
4. Willing and able to give informed consent
5. Willing to follow either dietary intervention assigned to them upon randomization.
6. Able to come in for all assessment visits.

Exclusion Criteria:

1. Participants who are currently diagnosed with diabetes mellitus, cardiovascular disease, liver or kidney disease, cancer
2. Current severe psychiatric illnesses (e.g. psychosis, schizophrenia, bipolar disorders, depression
3. Current suicidal ideation, and recent or past suicide attempts
4. History of psychiatric hospitalization (past year).
5. History of diagnosed eating disorders such as bulimia nervosa, anorexia nervosa and severe binge eating disorder.
6. History of diagnosed substance abuse or alcohol abuse.
7. Currently on any weight loss diet.
8. Having lost in the past 3 months 10% or more of body weight.
9. Unwilling or unable to give informed consent.