Inclusion Criteria:

• * Current resident of Boston public housing development
• * No plans to move within the next 6 months and no plan on leaving the country for more than 2 months over the next year
• * Able to read and speak in English or Spanish
• * Has cell phone with a plan that allows for unlimited text messages
• * Willing to wear a device to track physical activity during assessment periods

Exclusion Criteria:

• * Currently enrolled in a comprehensive weight loss program or a research study about weight that is incompatible with study participation
• * Currently on a medically prescribed diet or fast that is incompatible with study participation
• * Currently has a diagnosis of bipolar disorder, mania, manic-depressive disorder, schizophrenia, or psychosis and is not on any medications to treat the condition
• * Precontemplation stage of change for making healthy eating or physical activity changes
• * Pregnancy
• * Medical contraindications to physical activity. Self-reported presence of any of the following:
• * Can not walk without help from someone else
• * Regularly needs to use the following special equipment to walk or get around: wheelchair, scooter, walker, or extra oxygen
• * Gets short of breath even when using special equipment at a very low level of physical activity such as walking around the home, making a bed, or taking a bath
• * Advised by a healthcare professional not to exercise and or if diagnosed with a bone or joint problem, it could get worse.
• * Frequently gets pains in the heart or chest
• * Had a heart attack in the past 6 months
• * Often feels faint or has spells of severe dizziness
• * Has very high blood pressure that is often over 175 or the bottom blood pressure number is often over 110
• * Has a good physical reason not to follow an activity program even if they wanted to