Potato Research for Enhancing Metabolic Outcomes

Not Applicable

Completed

Interventions: Other: Reduced Meat High Potato Diet
Other: Reduced Meat High Pulses Diet

Brief Summary: The potato is a nutritious food that comprises approximately 30% of total vegetable intake in the United States (US). Consumption of pulses in the US is low but its contribution to health is frequently promoted. However, in the US diet, potatoes contribute as much dietary fiber, far more potassium, and a host of similar nutrients as pulses. When prepared to enhance its slowly digested starch content, potatoes produce a moderate glycemic response. In encouraging a shift towards plant-based foods and sustainable diets, the potato can partially replace meat in meat dishes to enhance the overall quality of the diet and reduce meat intake to recommended levels.

Detailed Description: Approximately 11% of individuals with untreated prediabetes progress to diabetes every year. Reversion to normal blood glucose concentrations reduces the incidence of diabetes by 56%. Healthy eating patterns such as the DASH and the Mediterranean Diet have shown that high intakes of fruits, vegetables, whole grains, legumes or pulses, and potatoes are associated with cardiometabolic health. In contrast, dietary patterns rich in meat and sugar-rich foods are associated with increased risk of mortality, type 2 diabetes, and coronary heart disease. These findings suggest that it may be prudent to replace certain foods with fruits and vegetables rather than simply embrace plant-based diets. Small changes that bestow health benefits are likely to be sustainable in the long-term. The objective of the present application is to develop a diet intervention to reverse insulin resistance in an overweight or obese population. The central hypothesis is that in the context of an overall healthy eating pattern, potatoes and pulses will not differ in the glycemic and insulinemic responses, lipid profile, and hsCRP concentration they elicit.

Recruitment & Eligibility

Inclusion Criteria

Adults from 18 - 60 years of age
Body mass index between 25 and 40 kg/m2
No evidence of diabetes (fasting blood sugar <126 mg/dL).
HOMA-IR > 2
Willing to consume the study foods and refrain from eating other foods for eight weeks.

Exclusion Criteria

Have type 1 or type 2 diabetes currently being treated by medication.
Are being treated with medications that have a significant effect on insulin resistance, obesity, serum lipids, and metabolic rate, or medications that significantly increase body weight such as certain antidepressants, second-generation antipsychotics, systemic glucocorticoids, and adrenergic blockers or stimulators.
Current pregnancy or breastfeeding.
Women of childbearing potential who are not using an effective method of birth control (i.e., barrier method, intrauterine and cervical devices, oral contraceptives, hormonal injections (Depo Provera® ), condoms with spermicidal gel or foam, contraceptive patch (Ortho Evra), diaphragm, or abstinence), are not surgically sterilized (including tubal ligation and hysterectomy), or not at least two years postmenopausal. All women of childbearing potential will have a pregnancy test performed prior to starting the study treatment in each cohort. If a subject becomes pregnant during the study, they will be dropped from the study.
Have clinically significant abnormal laboratory markers (as determined by the medical investigator).
Have contraindications to participation in a diet intervention.
Are unable to provide a baseline blood sample.
Have any condition that impedes testing of the study hypothesis or makes it unsafe to consume the foods being tested in the study (determined by the investigative team).

Arm && Interventions

Group	Intervention	Description
Potatoes Lean Meat (PLM)	Reduced Meat High Potato Diet	The main entrée in the PLM arm will consist of a menu item in which 40% of the meat in the original recipe will be replaced with potatoes. The diet is designed to provide six or less ounces of meat/day which is consistent with the DASH diet.
Lean Meat Pulses (LMP)	Reduced Meat High Pulses Diet	The main entrée in the LMP arm will consist of a menu item in which 40% of the meat in the original recipe will be replaced with pulses. The diet is designed to provide six or less ounces of meat/day which is consistent with the DASH diet.

Primary Outcome Measures

Name	Time	Method
Glycemic Response to the Diet	Baseline and 8 weeks	Change in area under the curve for blood glucose (mg/dL/min) concentration in response to the diet. Negative values are considered a better outcome.

Secondary Outcome Measures

Name	Time	Method
LDL Particle Size Response to the Diet	Baseline and 8 weeks	change in LDL particle size (nm) in response to the diet. Negative values are considered a better outcome.
Insulin Response to the Diet	Baseline and 8 weeks	change in area under the curve for blood insulin (uU/mL/min) concentration in response to the diet. Negative values are considered a better outcome.
Cholesterol Response to the Diet	Baseline and 8 weeks	change in blood cholesterol (mg/dL) concentration in response to the diet. Negative values are considered a better outcome.
Triglyceride Response to the Diet	Baseline and 8 weeks	change in blood triglyceride (mg/dL) concentration in response to the diet. Negative values are considered a better outcome.
hsCRP Response to the Diet	Baseline and 8 weeks	change in hsCRP (mg/L) in response to the diet. Positive values are considered a worse outcome.