To compare a caloric supplement containing peptides and medium-chain triglycerides, a caloric supplement containing whole protein and long-chain triglycerides, and no caloric supplement for the prevention of weight loss in individuals with AIDS who take a daily multivitamin and mineral supplement.

Patients will be randomized to one of 3 study arms:

Arm 1 - Peptamen drinks + multivitamin and mineral supplement, taken in addition to regular diet for 4 months Arm 2 - NuBasics drinks or equivalent amounts of NuBasics soups or bars + multivitamin and mineral supplement, taken in addition to regular diet for 4 months Arm 3 - Multivitamin and mineral supplement, taken in addition to regular diet for 4 months.

At months 0, 2, and 4, patients will be assessed for weight, body cell mass, patient-reported physical activity level, and dietary intake (by 24-hour dietary recall). At months 2 and 4, they will also be assessed for compliance with study regimen. Patients who complete their 4 month follow up visit will be provided with a 30 day supply of the caloric supplement of their choice (Peptamen or NuBasics) and a 30 day supply of the study multivitamin supplement.

Inclusion Criteria

Patients must have:

• HIV infection.
• Stable weight.
• CD4+ cell count <200 cells/mm3.
• Life expectancy of at least 6 months.
• Parent or legal guardian to sign written, informed consent for patients < 18 years old.

Exclusion Criteria

Co-existing Condition:

Patients with any of the following symptoms or conditions are excluded:

• Active opportunistic infection, requiring acute treatment.
• Malignancy (other than stable cutaneous Kaposi's sarcoma that does not require systemic chemotherapy).
• Diabetes mellitus or other conditions requiring special dietary restrictions.
• Body mass index (BMI) >= 29.0 kg/m2.
• Disorders or conditions that, in the treating clinician's opinion, may prevent adequate compliance with protocol requirements.

Concurrent Medication:

Excluded:

• Growth hormone.
• Megestrol acetate (Megace).
• Cyproheptadine (Periactin).
• Dronabinol (Marinol).
• Thalidomide.
• Anabolic steroids (e.g., nandrolone decanoate)(Deca-durabolin).
• Pharmacologic-dose corticosteroids (e.g., > 15 mg/day prednisone equivalent)

NOTE:

• Men requiring testosterone replacement therapy for documented hypogonadism may be enrolled.
• Caloric nutritional supplements deemed by the clinician to promote weight gain or maintenance.

Patients with the following prior condition are excluded:

• History of phenylketonuria.

Prior Medication:

Excluded within the past 2 weeks:

• Use of caloric nutritional supplements for more than 5 days deemed by the clinician to promote weight gain or maintenance.

Excluded within the past 30 days:

• Growth hormone.
• Megestrol acetate (Megace).
• Cyproheptadine (Periactin).
• Dronabinol (Marinol).
• Thalidomide.
• Anabolic steroids (e.g., nandrolone decanoate)(Deca-durabolin)
• Pharmacologic-dose corticosteroids (e.g., > 15 mg/day prednisone equivalent).

NOTE:

• Men requiring testosterone replacement therapy for documented hypogonadism may be enrolled.

HIV-infected participants who take a daily multivitamin and mineral supplement