Keto made easy

Blood Tests to Get Before Starting Keto

Quick answer: Ask your doctor for a baseline before you change anything: a lipid panel, fasting glucose and HbA1c, kidney function, and a basic electrolyte panel, plus anything your own history calls for. Then recheck a few months in. Without a baseline, "my LDL went up" is a scare with no context; with one, it's a number you and your doctor can compare and act on.

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Why the baseline matters more than the test

Here's the problem without one. You're four months into keto, you feel great, you get routine bloodwork, and your cholesterol looks different. Is that keto? Was it always that way? Is it going up or down? Nobody can say, because there's nothing to compare it to.

A baseline is the "before" photo for your blood. It costs one blood draw before you start, and it turns every later result into a trend instead of a mystery.

It also protects you from the internet. If a friend sends you a scary article, you can answer with your own numbers.

How to get your baseline, step by step

  1. Book the appointment before you change your diet. A baseline drawn after you start is no longer a "before," so test first, then start.
  2. Tell your doctor the plan. "I'm going to try a low-carb, ketogenic diet, under about 50 g of carbs a day. I'd like a baseline so we can check how it's going." A plan gets a better response than a request out of nowhere. See how to talk to your doctor about keto.
  3. Ask about these tests by name: - lipid panel (total cholesterol, LDL, HDL, triglycerides) - fasting glucose and HbA1c - kidney function (often creatinine and eGFR) - basic electrolytes (sodium, potassium) - anything your history suggests: thyroid, liver, uric acid, iron or B12 if you've had problems before
  4. Ask whether you should fast. Some panels are drawn fasting. Ask the office, don't guess.
  5. Check your insurance first. KetoDick suggests confirming what your insurance covers before you go (video cTGYIFOTPl8).
  6. Get a copy of the results. Keep them somewhere you'll find them in six months, with the date.
  7. Put the recheck on the calendar now. The baseline is only useful if there's a second test.

If you take medication for diabetes or blood pressure, or have kidney disease, this isn't optional, and the conversation is about more than labs. Your doses may need to change as you cut carbs. See keto and medications.

What each test tells you

Lipid panel. This is the one people worry about. On low-carb diets, triglycerides tend to fall and HDL tends to rise, while LDL responds differently from person to person. You won't know which kind of responder you are without a before and after. More in keto and cholesterol.

Fasting glucose and HbA1c. Fasting glucose is a snapshot; HbA1c reflects your average blood sugar over roughly the past few months. If you're starting keto partly for blood sugar, these are your scoreboard.

Kidney function. Two reasons it matters. If your kidneys are already impaired, high protein intake and electrolyte changes are things to manage with your doctor. And people with type 2 diabetes are a group KetoDick specifically says to bring to the doctor, because he says they often have some subclinical kidney issue (video GojQvo_2GS0).

Electrolytes. A baseline sodium and potassium matters if you plan to use light salt or take any blood pressure medication. It's also useful if you ever get symptoms like palpitations.

When to recheck

There's no single rule for this on the evidence pages. KetoDick's suggestion is to compare against your baseline at 6–12 months (video GojQvo_2GS0), and he also says some people's lipids become a problem around six months, which is why he planned to watch his own (video 1m1hPgaRIg4).

A reasonable plan: let your doctor set the recheck date, and if they don't, ask for one somewhere in that 3–12 month window. If you're on diabetes or blood pressure medication, the follow-up will likely be sooner and more frequent; that's their call.

What the research says

KetoDick's take

He's been saying "get a baseline" since 2017. Older people and anyone with health history should get baseline values from a doctor before starting, he says, so there's something to compare at 6–12 months (video GojQvo_2GS0). In his "keto is dangerous" video, his answer to worried friends is to check blood work and talk to your doctor (video 1m1hPgaRIg4).

On cholesterol, his reading and the literature don't line up perfectly, so here are both. He says he has read that about one in four people on low-carb high-fat diets develop a blood-lipid problem (video cTGYIFOTPl8), and in a later video that cholesterol markers may spike early and improve over 6–12 months (video UygKGoP_BtA). The evidence pages don't give a one-in-four figure or confirm an early-spike-then-improve pattern; what they show is that LDL responses vary by person and, in trials averaged together, went up. Either way, the practical answer is the same one he gives: test before, test after, and let your doctor read the trend.

Key takeaways