Dietary guidelines put to the test: does weight loss boost heart benefits?
NCT ID NCT04293224
First seen Jun 26, 2026 · Last updated Sep 10, 2026 · Updated 5 times
Summary
This study is testing whether following a Mediterranean-style diet based on U.S. dietary guidelines improves heart health more when combined with weight loss. Researchers will provide all meals for 70 adults with obesity or excess body fat for eight weeks. Participants will be split into groups: some will eat enough to maintain weight, while others will eat less to lose weight. The goal is to see if weight loss adds extra benefits for blood sugar, cholesterol, and blood pressure.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- Mediterranean diet pattern
- What this could lead to
- If successful, this could show that combining a healthy diet with weight loss is better for heart health than diet alone.
- What could go wrong
- This is a small, early-stage study (70 people) that only looks at short-term changes. Results may not apply to everyone, and the diet is provided, which may not reflect real-world eating habits.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
-
Not a phased trial
Phase numbers describe drug development. The registry uses this when they do not apply, as it does for trials of devices, procedures or behaviour changes, and for observational studies.
- Participants
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54 people
The number who actually took part.
- Started
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Aug 2022
- Finished
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Jul 2026
- Lead sponsor
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A government agency
The lead sponsor is a US federal agency other than the NIH.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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19 to 64 years
- Sex
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Female participants only
- Healthy volunteers
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Accepted
You do not need to have the condition being studied to take part.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: * Body Mass Index (BMI) 23-39.9 kg/m2 or 32-50% body fat percentage * Willingness to have blood drawn * The criteria listed above and at least one of the following: Fasting glucose ≥100 mg/dL but \<126 mg/dL or Fasting triglyceride ≥125 mg/dL or HDL-cholesterol ≤50 mg/dL or Blood Pressure (BP): Systolic BP ≥130 mmHg or Diastolic BP ≥85 mmHg or Hemoglobin A1C ≥ 5.7 and \<6.5% Exclusion Criteria: * Active participation in another research study * Tested positive for COVID-19 within the past 10 days * Been in close contact with a COVID-19 positive person within the past 14 days * Blood Pressure (BP): Systolic BP ≥140 mmHg or Diastolic BP ≥90 mmHg * LDL cholesterol ≥190 mg/dL * Triglycerides ≥500 mg/dL * Current use of smoking or chewing tobacco, e-cigarettes, cigars, vaping, cannabis or other use of nicotine containing products (within the past 6 months) * Current use of dietary supplements and/or unwillingness to cease intake of dietary supplements * Vegan or vegetarian lifestyle or any other dietary restrictions that would interfere with consuming the intervention foods and beverages (including dietary intolerances, allergies and sensitivities) * Unwillingness to consume intervention foods and beverages * Engage in more than moderate drinking (\> 1 drink serving per day) or binge drinking (4 drinks within two hours). * Unwillingness to cease alcohol intake as required for specific duration of the study * Excessive intake of caffeine containing products (excessive defined as ≥ 400 mg/day) * Unwillingness to refrain from caffeine intake on lab visit days. * Intentional weight change of ≥5% of body weight within 6 months of entry into the study * Diagnosis of disordered eating or eating disorder * Recent diagnosis of any of the following or measurement on screening lab tests: Anemia (hemoglobin \<11.7 g/dL) or abnormal liver or thyroid function (defined as liver enzymes that are \>200% of upper limit (ALT upper limit is 43 U/L or Aspartate transaminase (AST) upper limit is 54 U/L) and thyroid function tests: Thyroxine (T4, free) \<0.56 or \>1.64 ng/dL; Thyroid-stimulating hormone (TSH) \<0.35 or \>5.6 μIU/mL). * History of any of the following: Gastric bypass surgery, inflammatory bowel disease (IBD) or other GI conditions that would interfere with consuming the intervention foods, active cancer in the past three years excluding squamous or basal cell carcinomas of the skin that have been handled medically by local excision and other serious medical conditions * Recent dental work or have conditions of the oral cavity that would interfere with consuming the intervention foods and beverages * Taking any medication in the class of antipsychotics * Long term use of antibiotics * Taking any over the counter or prescribed medication for any of the following: Elevated lipids, elevated glucose, high blood pressure, weight loss or conditions that require corticosteroids (e.g. asthma, arthritis or eczema). * Are pregnant, planning to become pregnant within the duration of the study or breastfeeding.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
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UC Davis, Western Human Nutrition Research Center
Davis, California, 95616, United States
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