This is a randomized-controlled unblinded clinical trial to investigate dietary intervention on metabolic biomarker assessment in World Trade Center (WTC) Lung Injury (LI) in firefighters. The purpose of this study is to evaluate biomarkers of metabolic dysregulation that have previously been found to predict WTC-LI in a case cohort study selected from the entire exposed firefighter cohort, and attempt to alter these metabolites using dietary intervention and a technology-supported behavioral modification program. Investigators will measure Pre/Post global metabolic expression in WTC-exposed, symptomatic firefighter serum sampled after 6-month intervention, as well as clinical outcomes of WTC-LI in the study group vs controls.

Investigators propose to measure metabolites on this expanded cohort with serum sampled before and after 6-month intervention with calorie restricted Mediterranean diet to: 1) determine the effects of a technology assisted calorie restricted diet on metabolic risk and lung function; 2) determine differences between usual care and intervention group using genomics and metabolomics that may be targetable markers for further evaluation; 3) quantify the metabolome and evaluate pre/post changes in BMI, FEV1, FeNo, vascular stiffness, and overall quality of life; and 4) explore dietary modification as treatment of WTC-LI. The biomarker profile of the cohort control will be useful for discovering biomarker associations with other disease manifestations such as: bronchial wall thickening on CT, obstruction on FEV1 /FVC ratio, bronchodilator response, methacholine reactivity, and other definitions of loss of FEV 1 . This cohort control will be an asset to future studies.

Inclusion Criteria:

1. Age 21-90.
2. Born male sex and currently identify as genetic male
3. FDNY rescue and recovery worker.
4. Documented WTC exposure.
5. Enrolled in the FDNY WTC Health Program
6. Subjects are willing and able to consent for themselves to study enrollment
7. Subjects are willing and able to participate in study procedures
8. Are able to perform their activities of daily living independently
9. Are either light duty or retired FDNY Firefighters
10. Have an FEV1 less than the LLN of predicted for age/sex/weight documented at any time after 9/11/2001.
11. Have a BMI>27 kg/m2 and <50kg/m2
12. Willing and able to modify their diet and activity level.
13. Subjects who have a spirometry available within the last 36 months, and at their post-9/11 visits at the FDNY
14. Demonstrate minimal proficiency using a smart phone
15. Have means to accommodate transportation to/from in-person visits

Exclusion Criteria:

1. Have pre-existing and documented conditions or concurrent diagnoses, including (and not necessarily limited to) active cancer, severe heart disease, significant cognitive impairment, eating disorders, significant psychiatric illness, end-stage COPD, severe pulmonary hypertension, or organ transplant.
2. Concomitant use of interfering medication(s) or devices currently or within the month prior to enrollment, including anti-retrovirals, human monoclonal antibodies, supplemental daytime oxygen, and insulin pumps.
3. Severe gastrointestinal issues or illnesses that would prevent adherence to the proposed diets.
4. Severe kidney disease requiring dialysis
5. Severe liver disease requiring frequent medical intervention
6. Participating in other diet modification studies.
7. High dose steroid (>20mg prednisone or equivalent) or other hormonal treatments/chemotherapy use in the last month, including testosterone supplementation.
8. Life-expectancy < 6 months
9. BMI ≥50 kg/m2 or ≤27 kg/m2
10. Recent significant intentional or unintentional weight loss, defined as over 5% reduction in total body weight over the last month. (Blackburn Criteria).
11. Significant or severe alcohol abuse disorder

Male only

FDNY rescue and recovery worker with 9/11 exposure with documented WTC-LI by spirometry criteria.