What kind of doctor works up metabolic health, and what should the workup include?

What kind of doctor treats insulin resistance and metabolic health?

An internal medicine physician, often called an internist, or a family physician treats insulin resistance and the wider metabolic picture. Both are trained to manage blood sugar, blood pressure, cholesterol, weight and the liver together, which is what metabolic health means: how well the body handles and stores energy. Underneath most of it sits insulin resistance, in which cells respond less well to insulin, the hormone that moves sugar out of the blood, so the body has to make more of it. Roughly 4 in 10 American adults without diabetes have it [PMID: 40364246], and by one national estimate fewer than 7 in 100 adults have optimal weight, blood sugar, blood fats and blood pressure with no cardiovascular disease [PMID: 35798448].

An endocrinologist, a physician who specializes in hormones and metabolism, is the right addition when the picture is complicated: diabetes that has become hard to control, type 1 diabetes, a suspected disorder of the thyroid, adrenal or pituitary glands, or a presentation that does not fit the usual pattern. Other specialists join for their part, while one physician holds the whole picture and decides what comes first.

The first visit should be mostly history: how weight and energy have changed over the years, sleep, the cycle history in women, the family history, what has been tried, and every medication. The tests follow from that history.

Functional, integrative and precision medicine: what do the words mean?

They name approaches to care, not specialties or licences, and they overlap more than they differ.

• Functional medicine asks why a symptom or result is happening and looks across systems for the answer: hormones, metabolism, inflammation, the gut, nutrients, sleep and stress.
• Integrative medicine combines conventional care with attention to nutrition, movement, sleep and stress, and with complementary therapies where the evidence supports them.
• Precision medicine fits prevention and treatment to the individual, not the average: their genes, biomarkers, history and measured response.
• Longevity medicine applies the same thinking to a long horizon: finding the risks of later life early and acting while they are small.

None of these words describes training. In a physician's hands they describe how the work is done on top of a licence and a specialty: a board-certified internal medicine physician with training in functional, integrative and longevity medicine is still, first, an internist.

Are functional medicine doctors legitimate?

The question has a more useful version: is this particular doctor legitimate? Functional medicine is an approach, not a licence and not a specialty that a medical board certifies, so the label settles nothing in either direction. It is used by physicians, nurse practitioners, chiropractors, naturopathic doctors, dietitians and health coaches, each working within the scope their own licence sets. What can be checked is the person: an active licence on the state medical board's public lookup, and board certification in the specialty board's public directory. Certificates in functional medicine can reflect real additional study; they sit on top of a licence and a specialty and replace neither.

A strong practice, whatever it calls itself, shows in how it works: a full history before any testing, tests whose meaning is established, plain talk about what is well supported and what is still early, and cooperation with the patient's other doctors. Research on the model as a whole is young. A retrospective study at one academic medical center found that patients seen in a functional medicine clinic reported somewhat larger gains in physical health at six months than matched primary care patients; at twelve months the difference was no longer statistically significant, and the authors called for prospective studies [PMID: 31651966]. The individual pieces, such as lifestyle change for blood sugar and the treatment of blood pressure and cholesterol, rest on much firmer ground.

What should a metabolic workup include?

A metabolic workup should include a careful history, a few measurements that can be taken in a clinic or at home, and a set of ordinary blood tests read together.

• Fasting insulin and fasting glucose. Glucose is the last number to move. In a long-running British study, insulin sensitivity was already falling steeply five years before diabetes was diagnosed, while fasting glucose rose sharply only in the final three [PMID: 19515410].
• HbA1c. Average blood sugar over the past few months, most useful as a trend.
• A lipid panel that includes ApoB. ApoB, a protein carried once on every cholesterol particle that can enter the artery wall, counts those particles directly, and there is substantial evidence that it gauges that risk more accurately than LDL cholesterol [PMID: 31642874].
• Liver enzymes. Roughly 3 in 10 people worldwide have fat in the liver [PMID: 36626630], usually without symptoms. Liver enzymes can be normal across the whole range of the condition, scarring included [PMID: 12774006], so they are read alongside waist and triglycerides.
• Blood pressure. Measured more than once, ideally with readings taken at home.
• Waist and body composition. Waist circumference estimates the fat carried around the organs. A body composition scan, usually DEXA, a low-dose X-ray scan, separates fat from muscle and shows where the fat sits.
• Sleep. In a small study of healthy adults, one night cut to four hours measurably reduced insulin sensitivity the next day [PMID: 20371664]. Loud snoring and pauses in breathing point toward sleep apnea, which has its own test.
• A medication review. Several common classes of medication raise blood sugar or weight, among them steroid medications and some medications for mood and blood pressure.

The five measurements that define metabolic syndrome are all on that list: waist, blood pressure, triglycerides, HDL cholesterol and fasting glucose, with three abnormal findings out of five meeting the definition [PMID: 19805654]. A workup goes further because the point of looking is to see the problem forming. Depending on the history, a physician may add uric acid, a thyroid panel, sex hormones or a short run on a continuous glucose sensor, now sold over the counter.

Intense thirst, frequent urination, blurred vision or unexplained weight loss call for prompt medical evaluation, not a scheduled workup, and chest pain or pressure, trouble breathing or sudden weakness call for 911 or the nearest emergency department.

How do you find a good functional medicine doctor?

By checking four things that matter in any physician, whatever the practice calls itself. A search for the best functional medicine doctors near me returns rankings and directories, a reasonable way to collect names; the four checks show how a doctor works.

• Training you can verify. An active licence in the patient's state and board certification in a specialty such as internal medicine, family medicine or endocrinology, both confirmed through public directories. Added training is worth asking about: where it was done and what it covered.
• A reason for every test. Each test should answer a question, and the answer should be able to change the plan. A broad first panel can be a sensible start; what counts is what happens with each result.
• Accountability for the plan. One physician who orders and interprets the testing, takes responsibility for treatment decisions, including medication when lifestyle change is not enough, and works alongside the doctors already involved.
• Time between visits. Metabolic change happens over months, between appointments. Ask who answers when a result comes back, how the plan is adjusted when a number does not move, and when things are measured again.

One more question fits the metabolic picture: whether muscle, sleep and food get the same attention as medication.

Does insurance cover functional medicine doctors?

It varies. Coverage follows the plan, the clinician and the service, not the name of the approach: some physicians who practice this way are in insurance networks, and many such practices are private-pay, meaning the patient pays the practice directly. The reliable answer comes from asking the practice whether it bills insurance and asking the plan what it covers. Extend Medical is private-pay, not billed through insurance.

How much does a functional medicine doctor cost?

It varies widely, and a figure means little until it is clear what it includes. Practices differ in whether they charge by the visit or for a defined period of care, in whether the fee covers time between visits and the review of results, and in whether laboratory tests and imaging are included or billed separately.

A few questions make fees comparable. What does the fee cover, and what is billed separately? Who reviews results, and how soon? How does follow-up work, and who answers between visits?

How does care by video work?

Care by video suits metabolic health because the workup runs on conversation, blood tests and a few simple measurements, which is also the answer for anyone looking for an online functional medicine doctor. The history is taken on screen. Blood is drawn at a laboratory near the patient, any scan is booked at a center near them, and a home blood pressure cuff and a tape measure supply the rest. When something needs an examination or a procedure, the physician coordinates with the patient's primary care physician or a local specialist. Distance to an office stops being the deciding factor.

How do you start?

The way into care at Extend Medical is the Work with Dr. Paul form; once it is submitted, an email arrives with the next steps. Care is private-pay, as noted above. The first conversation is the history in full, along with any recent results already in hand.

The deeper picture

Metabolic health is the part of medicine where the distance between a number and a plan is greatest. The tests are ordinary; the work is in reading them against one person's history, deciding which finding matters most, and choosing what to address first among sleep, muscle, food, stress and medication. It is also where acting early reaches furthest. In a trial that followed adults with impaired glucose tolerance, an early stage of blood sugar trouble, for thirty years, six years of structured support with diet and exercise delayed diabetes by about four years and was followed by about a quarter fewer cardiovascular events and deaths from any cause [PMID: 31036503]. That is the horizon a metabolic workup is for: the numbers in front of the physician, and the decades they point to.