The primary objective is to assess the effect of short-term diet modification on the microbiome composition, and inflammatory/metabolic disease markers in Antiretroviral therapy (ART)-treated HIV-infected participants and Human immunodeficiency virus (HIV)-negative controls in the United States.

This is a randomized clinical trial. Fifty (50) Antiretroviral therapy (ART)-treated Human immunodeficiency virus (HIV) positive participants, 24 HIV negative controls matched for age and sex, and 24 HIV negative controls from a population at high risk for contracting HIV will be recruited into 3 cohorts. All participants will undergo a 4 week diet modification and will be randomly assigned to receive either an Agrarian diet or a Western-type diet. For the first 2 weeks, food will be provided to the participant, followed by an additional 2 weeks where participants will be provided a diet menu with recipes to prepare themselves. There will be 4 study visits and participation will last for up to 2 months.

Inclusion Criteria:

• HIV-infected cohort (Cohort A)

  • Documentation of HIV-1 infection defined as a positive antibody test or plasma HIV-1 RNA (ribosomal ribonucleic acid).
  • Treated with ART (minimum of three antiretroviral drugs in regimen) for at least 12 months with no changes in antiretroviral drugs over the past 6 months
  • Plasma HIV-1 RNA ≤ 50 copies/mL in the preceding 6 months.

• HIV-negative cohorts (Cohort B and C)

  • Documentation of a negative HIV-1 antibody test

• All Cohorts

  • Age 18 to 65 years
  • Body mass index between 21-29 kg/m2 (non-obese)
  • Stable weight for at least 3 months (≤15% change in body weight)
  • Negative pregnancy test (if female)

Exclusion Criteria:

• Use of systemic (oral or parenteral) antibiotics within two months prior to study entry
• Active chronic infection such as hepatitis B or C or an active malignancy that requires systemic chemotherapy.