This is a 4-month randomized trial of a prolonged nightly fasting intervention (PROFAST) in 40 overweight and obese individuals with monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM), and smoldering waldenstrom macroglobulinemia (SWM). The purpose of this study is to understand if fasting for a prolonged period of time during the nighttime hours is a strategy to prevent overweight and obese individuals from developing blood cancer.

Participants will be randomized into the following two groups:

• Group A: PROFAST intervention for 4 months
• Group B: Healthy Lifestyle Control group for 4 months

The purpose of this research study is to learn if fasting for a prolonged period of time could be used in the future to help improve body composition and prevent blood cancer in overweight and obese individuals with MGUS, SMM, and SWM. Multiple myeloma is a cancer of the plasma cells, which is an important part of the immune system. Participants with active multiple myeloma generally require treatment. There are currently no approved therapies or prevention strategies for smoldering multiple myeloma or monoclonal gammopathy of undetermined significance.

The National Cancer Institute of the National Institutes of Health is supporting this research study by providing funding.

This research study is a 4-month randomized trial of prolonged nightly fasting (PROFAST). It is expected that about 40 people will take part in this research study. The total study duration is 4 months.

Participants in the study will be randomized, in equal numbers to either the nightly fasting intervention group or a control group.

• The prolonged nightly fasting (PROFAST) intervention involves gradually working up to a 14-hour fast during the nighttime hours. Participants will be supported by means of calls with a health coach during the first 4 weeks of the study. Participants will also be asked to use a text messaging platform to record their first and last meal of the day, and will receive personalized feedback based on the meal times via the text messaging system. The text messaging system will be used throughout the duration of the study.
• For participants randomized to the control group, an introductory session with a health coach and educational information will be provided. Participants will also receive one email and one text message per week with tips on healthy living during the 4 months of the study.

Inclusion Criteria:

• BMI >= 25 kg/m2
• Documented diagnosis of MGUS or Smoldering MM(SMM) or Smoldering Waldenstrom Macroglobulinemia(WM) via EMR review. *note: please review case with PI or treating MD if diagnosis is uncertain.
• At least 18 years of age
• Currently fasting for <14 hours per night, as assessed using 24-hour food recalls
• Owns a cell phone and is comfortable sending and receiving text messages
• Ability to understand and the willingness to sign a written informed consent document

Exclusion Criteria:

• Diagnosis of overt MM or WM
• Patients diagnosed with another malignancy requiring active therapy
• Clinical diagnosis of diabetes, which may increase the risk of hypoglycemia with a prolonged fast. Note: patients with diabetes may enroll with consent from MD that manages their clinical care.
• Any other condition that, in the investigator's judgment, would contraindicate prolonged nightly fasting or otherwise interfere with participation in the trial, including night shift work, night eating syndrome, taking weight loss medication, or participation in another weight loss program