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