What laboratory tests should be ordered for a 24-year-old trying to lose weight who has tried multiple diets and exercise regimens?

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From the Guidelines

For a 24-year-old trying to lose weight who has tried multiple diets and exercise regimens, I recommend a comprehensive metabolic workup including thyroid function tests (TSH, free T4), fasting blood glucose, hemoglobin A1C, lipid panel, complete blood count, comprehensive metabolic panel, and vitamin D levels, as these tests can help identify underlying medical conditions that may be impeding weight loss efforts, as suggested by the American Psychiatric Association practice guideline for the treatment of patients with eating disorders 1. When evaluating a patient who is struggling with weight loss, it is essential to consider potential underlying medical conditions that may be contributing to their weight loss challenges.

  • Thyroid disorders, such as hypothyroidism, can affect metabolism and make weight loss more difficult, despite appropriate lifestyle modifications 1.
  • Insulin resistance and hormonal imbalances, such as polycystic ovary syndrome (PCOS), can also impact weight loss efforts, as they can lead to changes in appetite, metabolism, and fat distribution 1.
  • Nutritional deficiencies, such as vitamin D deficiency, have been linked to obesity and may need to be addressed through supplementation or dietary changes 1. Additional tests to consider include insulin levels, cortisol levels, and sex hormone panels (testosterone, estrogen, progesterone), as these can provide further insight into potential underlying medical conditions that may be impacting weight loss efforts, as recommended by the American Heart Association 1. It is crucial to note that the American Psychiatric Association practice guideline for the treatment of patients with eating disorders recommends a comprehensive review of systems, including laboratory assessments, such as a complete blood count and comprehensive metabolic panel, to identify co-occurring health conditions 1. By ordering these laboratory tests, healthcare providers can determine if medical intervention is needed alongside lifestyle changes to achieve weight management goals, ultimately improving patient outcomes and reducing the risk of morbidity and mortality associated with obesity, as emphasized by the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the Obesity Society 1.

From the Research

Laboratory Tests for Weight Loss

To determine the appropriate laboratory tests for a 24-year-old trying to lose weight who has tried multiple diets and exercise regimens, consider the following:

  • A comprehensive metabolic panel to assess glucose and lipid metabolism, as well as liver and kidney function 2
  • Thyroid function tests to rule out hypothyroidism, which can affect weight loss 2
  • Complete blood count to assess for any underlying inflammatory or infectious processes that may be contributing to weight loss difficulties 2
  • Fasting insulin and glucose levels to assess insulin sensitivity and glucose metabolism 2
  • Lipid profile to assess cholesterol and triglyceride levels 3, 2

Considerations for Weight Loss Strategies

When considering weight loss strategies, the following points are relevant:

  • Eating less fat and exercising more have been associated with successful weight loss 3
  • Using prescription weight loss medications may also be effective for some individuals 3, 2
  • Joining commercial weight loss programs may be beneficial for some people 3
  • Liquid diets, nonprescription diet pills, and popular diets have not been shown to be effective for long-term weight loss 3, 4
  • A personalized approach to weight loss, taking into account individual factors such as genotype and phenotype, may be beneficial, but more research is needed to support this approach 2

Potential Risks of Weight Loss Strategies

It is also important to consider the potential risks of weight loss strategies, including:

  • Weight regain, which is common after intentional weight loss 4
  • Increased risk of cardiometabolic diseases, such as diabetes and heart disease, associated with repeated cycles of weight loss and regain 4
  • Potential negative effects of dieting on mental and physical health, particularly in young people 5, 4

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Successful weight loss among obese U.S. adults.

American journal of preventive medicine, 2012

Research

Pathways from dieting to weight regain, to obesity and to the metabolic syndrome: an overview.

Obesity reviews : an official journal of the International Association for the Study of Obesity, 2015

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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