Siblings of those with type 1 diabetes are at an increased risk of developing the disease themselves. Through prior research, the investigators have found that siblings as well as those with type 1 diabetes have a general level of inflammation in the body. The investigators are examining the role that diet plays in this level of inflammation by asking siblings of children with type 1 diabetes to go on a gluten and Amylase Trypsin Inhibitors (ATI)-free diet for 4 weeks. Blood and stool samples will be measured before the diet, after the diet is completed and again 4 weeks after participants resume their normal diet.

Inclusion Criteria:

1. Males and females 2-23 years of age
2. Full-sibling of an individual with a clinical diagnosis of type 1 diabetes
3. Treatment naïve of any immunomodulatory agent

Exclusion Criteria:

1. Abnormal HbA1c, defined as ≥ 6%
2. Previous or current use of a gluten-free diet
3. Current diagnosis of celiac disease
4. An elevated tissue transglutaminase IgA level (> 10 units/mL)
5. Chronic (≥ 3 months duration) gastrointestinal disease or presence of gastrointestinal symptoms within the prior 6 weeks (e.g., abdominal pain, worsening constipation, diarrhea, or recurrent nausea +/- vomiting)
6. Chronic inflammatory or autoimmune disease with the exception of well-controlled hypothyroidism or intermittent or mild persistent asthma not requiring the use of daily inhaled steroids
7. Use of any medications that affect glucose metabolism (e.g., metformin) or the immune system (e.g., use of any glucocorticoids (inhaled, intranasal, oral, intravenous) within the previous 3 months)
8. Use of any medications that could affect intestinal microbiota within the previous 3 months (e.g., antibiotics, prebiotics, or probiotics)
9. Any condition that, in the investigator's opinion, may compromise study participation or may confound the interpretation of the study results