LoBAG30 Diet in Patients on Metformin

Not Applicable

Terminated

Brief Summary: We will determine the metabolic response to a Low Biologically Available Glucose Diet (LoBAG30) in subjects currently receiving the maximum dose of metformin as monotherapy in whom the glycohemoglobin is not at an acceptable level (\>8.0%). Our hypothesis is that introduction of a LoBAG30 diet to subjects currently treated with a full therapeutic dose of metformin will improve blood glucose control in people who have not achieved an acceptable total glycohemoglobin on metformin alone.

Detailed Description: Subjects will ingest a control diet (55% carbohydrate (CHO), 15% protein, 30% fat) or a LoBAG30 diet (30% CHO, 30% protein, 40% fat) in a parallel design with block randomization in pairs of two. Subjects will return to the study center twice each week while on the diets to have blood glucose, glycohemoglobin, lactate, weight and blood pressure measured, and to have urine assayed for urea and creatinine. At the beginning and end of the 5 week study period, the subjects will be admitted to the study center for 28 hours during which time blood will be drawn for 24 hour profiles of glucose, insulin, other hormones and several metabolites. For those subjects randomized to the LoBAG30 arm of the study, the control diet will be given during the first 24 hour study period; the assigned diet will be given at the end of the 5 week period.

Recruitment & Eligibility

Inclusion Criteria

People with type 2 diabetes mellitus who currently are receiving the maximal dose of metformin monotherapy (2500 mg/day).
These subjects will have had a stable glycohemoglobin (tGHb) in an unacceptably high range (8-11%) for at least 4 months prior to beginning the study.
Subjects with tGHB > 11% (HbA1c > 10%) will not be recruited into the study.

Exclusion Criteria

Hematological abnormalities
liver disease
kidney disease
macroalbuminuria (>300 mg albumin/24 hours)
untreated thyroid disease
congestive heart failure
angina
life-threatening malignancies
proliferative retinopathy
severe diabetic neuropathy
peripheral vascular disease
serious psychological disorders
a body mass index > 35
and a fasting triglyceride of >400 mg/dl.
- Subjects taking slow-release metformin will not be studied.
- Subjects taking medications other than metformin, known to affect fuel metabolism such as:
insulin
the sulfonylureas
glucagon-like peptide 1 (GLP-1) analogs and metabolic inhibitors
pramlintide
prednisone and similar steroids
thyroid hormone
antipsychotic medications
thiazide diuretics
medroxyprogesterone
high dose aspirin, also will be excluded.
- If concentrations of serum folate, B12 or iron are low, the subject will be excluded from the study until corrected, i.e. until normal concentrations are recorded.

Arm && Interventions

Group	Intervention	Description
Arm 1	LoBAG30 diet	A LoBAG30, weight maintenance diet will be given to subjects on metformin. All food will be provided for 5 weeks.
Arm 2	Control Diet	A weight maintenance, control diet consisting of 55% carbohydrate, 15% protein, 30% fat will be given to subjects on metformin. All food will be provided for 5 weeks.

Primary Outcome Measures

Name	Time	Method
Change in Body Weight at 5 Weeks From Baseline	baseline and 5 weeks after dietary intervention	Subjects were to remain weight stable. We expected less than 2 pound weight change over 5 weeks. Weight was measured before dietary intervention, and after 5 weeks of dietary intervention.
Change in Overnight Fasting Glucose Concentration at 5 Weeks From Baseline	baseline and 5 weeks after dietary intervention	Overnight fasting glucose concentration was measured before dietary intervention and after 5 weeks of dietary intervention.
Change in %Hemoglobin A1c at 5 Weeks From Baseline	Baseline and 5 weeks after dietary intervention	Hemoglobin A1c measured before and after 5 weeks on the diet
Change in Total Glucose Area at 5 Weeks From Baseline	Baseline and 5 weeks after dietary intervention	The area response is measured using zero as baseline. The area is measured before dietary intervention, and following 5 weeks of dietary intervention.

Secondary Outcome Measures

Name	Time	Method
Change in Fasting Triglycerides at 5 Weeks From Baseline	baseline and 5 weeks after dietary intervention	Overnight fasting triglycerides concentration was measured before dietary intervention and after 5 weeks of dietary intervention
Microalbumin Excretion	baseline and 5 weeks after dietary intervention	change in urinary albumin excretion was measured before dietary intervention and after 5 weeks of dietary intervention