Completed

The Safety and Efficacy of Low and High Carbohydrate Diets

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What is being tested

Low-calorie diet

+ low-carbohydrate diet
Behavioral
Who is being recruted

From 18 to 65 Years
See all eligibility criteria
How is the trial designed

Treatment Study

Phase 4
Interventional
Study Start: April 2003
See protocol details

Summary

Principal SponsorTemple University
Last updated: January 14, 2026
Sourced from a government-validated database.Claim as a partner
Study start date: April 1, 2003Actual date on which the first participant was enrolled.

Despite the considerable mass appeal of popular diet books, such diet approaches lack data to support their efficacy and safety. Despite its widespread use for more than 30 years, the Atkins diet has never been evaluated in a large, randomized, controlled trial. This study will assess the short-term and long-term clinical effects of a low-carbohydrate diet and a high-carbohydrate diet in overweight and obese men and women. Participants in this study will be randomly assigned to the Atkins diet (low-carbohydrate, unlimited fat and protein) or a conventional USDA diet (high-carbohydrate, low-fat). The study will evaluate the effects of each dietary approach on changes in: 1) weight and body composition; 2) metabolic and organ function; and 3) exercise tolerance. Each participant will be enrolled in the study for 2 years.

Official TitleThe Safety and Efficacy of Low and High Carbohydrate Diets 
NCT00079547
Principal SponsorTemple University
Last updated: January 14, 2026
Sourced from a government-validated database.Claim as a partner

Protocol

This section provides details of the study plan, including how the study is designed and what the study is measuring.
Design Details
307 patients to be enrolledTotal number of participants that the clinical trial aims to recruit.
Treatment Study
These studies test new ways to treat a disease, condition, or health issue. The goal is to see if a new drug, therapy, or approach works better or has fewer side effects than existing options.

How participants are assigned to different groups/arms
In this clinical study, participants are placed into groups randomly, like flipping a coin. This ensures that the study is fair and unbiased, making the results more reliable. By assigning participants by chance, researchers can better compare treatments without external influences.

Other Ways to Assign Participants
Non-randomized allocation: Participants are assigned based on specific factors, such as their medical condition or a doctor's decision.
None (Single-arm trial): If the study has only one group, all participants receive the same treatment, and no allocation is needed.

How treatments are given to participants
Participants are divided into different groups, each receiving a specific treatment at the same time. This helps researchers compare how well different treatments work against each other.

Other Ways to Assign Treatments
Single-group assignment: Everyone gets the same treatment.
Cross-over assignment: Participants switch between treatments during the study.
Factorial assignment: Participants receive different combinations of treatments.
Sequential assignment: Participants receive treatments one after another in a specific order, possibly based on individual responses.
Other assignment: Treatment assignment does not follow a standard or predefined design.

How the effectiveness of the treatment is controlled
In a non placebo-controlled study, no participants receive an inert substance (placebo) to compare outcomes. Instead, all participants receive either the experimental treatment or an alternative treatment (often the Standard of Care). This method allows researchers to compare the effects of the experimental treatment with those of a different active intervention, rather than a placebo.

Other Options
Placebo-Controlled: A placebo is used to compare the effects of the experimental treatment with those of an inert substance, isolating the true treatment effect.

How the interventions assigned to participants is kept confidential
Everyone involved in the study knows which treatment is being given. This is typically used when it's not possible or necessary to hide the treatment details from participants or researchers.

Other Ways to Mask Information
Single-blind: Participants do not know which treatment they are receiving, but researchers do.
Double-blind: Neither participants nor researchers know which treatment is given.
Triple-blind: Participants, researchers, and outcome assessors do not know which treatment is given.
Quadruple-blind: Participants, researchers, outcome assessors, and care providers all do not know which treatment is given.

Eligibility

Researchers look for people who fit a certain description, called eligibility criteria: person's general health condition or prior treatments.
Criteria
Any sexBiological sex of participants that are eligible to enroll.
From 18 to 65 YearsRange of ages for which participants are eligible to join.
Healthy volunteers allowedIf individuals who are healthy and do not have the condition being studied can participate.
Criteria

Inclusion Criteria * Body mass index between 30 and 40 * Live and work within 1 hour of the study site * Stable psychological status Exclusion criteria * History of heart disease, heart attack, or stroke * Blood pressure \>140/90 mmHg * Abnormal cholesterol levels * Significant psychiatric illness * Any medication that affects weight or metabolic rate * Presence or history of a chronic disease that is known to affect appetite, food intake, or metabolism (i.e., diabetes, thyroid disease, or cancer) * Currently using antidepressants, steroids, tobacco, or illegal drugs * Pregnant, breastfeeding, or planning pregnancy * 10 lb change in weight within 6 months of study entry * History of malignant arrhythmias or cerebrovascular, renal, or hepatic disease * History of protein wasting diseases or gout * Severe arthritis * Osteoporosis * Certain types of hormone replacement therapy * Currently following a vegetarian diet

Study Plan

Find out more about all the medication administered in this study, their detailed description and what they involve.
Treatment Groups
Study Objectives
2 intervention groups 

are designated in this study

This study does not include a placebo group 

Treatment Groups
Group I
Active Comparator
Low-calorie diet

low-calorie diet
Group II
Experimental
Low-carbohydrate diet

low-carbohydrate diet
Study Objectives
Primary Objectives

Secondary Objectives

Study Centers

These are the hospitals, clinics, or research facilities where the trial is being conducted. You can find the location closest to you and its status.
This study has 3 locations
Suspended
University of ColoradoDenver, United StatesSee the location
Suspended
Washington UniversitySt. Louis, United States
Suspended
University of PennsylvaniaPhiladelphia, United States
Completed3 Study Centers