Dairy intake and metabolic health in teens and older adults

Inclusion Criteria (long-term Study):

* Age 15-18 years old (adolescents) or 60-80 years old (seniors)
* BMI z-score \>+1SD, \<+2SD (adolescents) or BMI 25-34.9 kg/m2 (seniors)
* Waist circumference \> 80 cm for women and \> 94 cm for men (seniors)
* FBG 5.6-6.9 mmol/L (prediabetes)
* Willing to follow Canada's Food Guide
* Willing to maintain current dietary supplement use throughout the study.
* Willing to abstain from alcohol consumption for 24 hours before all test visits.
* Willing to avoid vigorous physical activity for 24 hours before all test visits.
* Understands the study procedures and is willing to provide informed consent by the parent/guardian and assent by participant to participate in the study and authorization to release relevant protected health information to the study investigator.

Exclusion Criteria:

* Fasting BG ≥ 7 mmol/L
* Blood pressure systolic ≥ 130mmHg or diastolic ≥ 80mmHg (adolescents) or systolic ≥ 140 mmHg or diastolic pressure ≥ 90 mmHg
* Smoking (tobacco and/or cannabis product use in the last 6 months)
* Thyroid problems
* History of CVDs, diabetes, liver or kidney disease, inflammatory bowel disease, celiac disease, short bowel syndrome, any malabsorption syndrome, pancreatitis, gallbladder, or biliary disease.
* Presence of gastrointestinal disorder or surgeries within the past year.
* Use of the prescription or non-prescription drugs, herbal or nutritional supplements known to affect the outcome of the study as per the investigator's judgment (including prebiotics and probiotics).
* Known to be pregnant, lactating, or not postmenopausal for at least a year and/or is taking hormonal treatments
* Unwillingness or inability to comply with the experimental procedures
* Known intolerance, sensitivity, or allergy to dairy, gluten, or any other study treatments.
* Consumption of protein powders/supplements
* Extreme dietary habits (e.g., Atkins diet, very high-protein diets, etc.)
* Weight gain or loss of \> 5% in the previous three months.
* Excessive alcohol intake (more than 2 drinks per day or 9 per week)
* Restrained eating, identified by a score of ≥11 on the Eating Habits Questionnaire

Inclusion Criteria (short-term study):

* Age 14-18 years old (adolescents) or 60-75 years old (older adults)
* BMI z-score \>+1SD, \<+2SD (adolescents) or BMI 25-30 kg/m2 (older adults)
* Willing to maintain habitual diet, physical activity pattern, and body weight throughout the study.
* Willing to maintain current dietary supplement use throughout the study. On study visit days, subject agrees not to take any supplements until dismissal from the Nutrition Intervention Center.
* Willing to abstain from alcohol consumption for 24hrs prior to all study visits.
* Willing to avoid vigorous physical activity for 24hrs prior to all study visits.
* Willing to refrain from cannabis use throughout the entire duration of the study.
* Willing to refrain from protein supplement use (e.g. protein powder) throughout the entire duration of the study.
* Understands the study procedures, provides informed consent to participate in the study, and authorizes release of relevant protected health information to the study investigator.

Exclusion Criteria (short-term study):

* Smoking
* Thyroid problems
* Lactose intolerance and/or allergies, intolerances, or sensitivities to study treatments
* Previous history of cardiovascular disease, diabetes, liver or kidney disease, inflammatory bowel disease, celiac disease, short bowel syndrome, malabsorptive syndrome, pancreatitis, gallbladder or biliary disease
* Presence of gastrointestinal disorder or surgeries within the past year.
* Inability to comply with the experimental procedures and follow our safety guidelines
* Regular breakfast skipping (\>3 days a week)
* On a special diet (e.g. ketogenic, Atkins, high protein) or restrained eaters as identified by a score of \>20 on the Eating Attitudes Questionnaire
* Difficulties with eating or swallowing
* Fasting blood glucose \>5.6mmol/L measured at screening
* Uncontrolled hypertension (systolic blood pressure \>120mmHg, diastolic blood pressure \>80mmHg) as defined by the average blood pressure measured at screening
* Weight gain or loss of \>10lbs in previous three months
* Consuming prescription or non-prescription drug, herbal or nutritional supplements known to affect outcome of the study as per investigator's judgement