Question 1

What is a normal HOMA-IR score?

Accepted Answer

Below 1.0 is optimal, 1.0-1.4 is normal. Above 2.0 indicates insulin resistance. Above 3.0 is severe insulin resistance associated with increased risk of type 2 diabetes.

Question 2

How is HOMA-IR calculated?

Accepted Answer

HOMA-IR = (Fasting Glucose in mg/dL × Fasting Insulin in µIU/mL) ÷ 405. Both tests require an overnight fast of 8-12 hours.

Question 3

Can you have insulin resistance with normal blood sugar?

Accepted Answer

Yes. Insulin rises years before glucose does because your pancreas compensates. HOMA-IR catches this early by looking at both glucose and insulin together.

Question 4

How often should I check my HOMA-IR?

Accepted Answer

Every 3-6 months if your score is elevated (above 2.0). Annually if your score is normal.

Question 5

What can I do to lower my HOMA-IR?

Accepted Answer

Exercise (especially resistance training), reduce refined carbohydrates, improve sleep quality, manage stress, and lose visceral fat.

Question 6

What does an A1C of 5.7 mean?

Accepted Answer

It is the threshold for prediabetes. Your average blood sugar has been slightly elevated over the past 2-3 months.

Question 7

How accurate is estimating A1C from average glucose?

Accepted Answer

The ADAG formula is reliable for most people but can be off in conditions affecting red blood cell lifespan, such as iron deficiency anemia or sickle cell trait.

Question 8

Can A1C be wrong?

Accepted Answer

Yes. Iron deficiency anemia can falsely raise A1C, while sickle cell trait or recent blood loss can falsely lower it.

Question 9

How often should A1C be tested?

Accepted Answer

Every 3 months if prediabetic or diabetic. Every 1-2 years if normal.

Question 10

What is the difference between A1C and fasting glucose?

Accepted Answer

Fasting glucose is a single snapshot. A1C reflects your average over 2-3 months, making it far more useful for detecting trends.

Question 11

What is the difference between BMR and TDEE?

Accepted Answer

BMR is calories burned at complete rest. TDEE includes all daily activity and is the number you actually need for nutrition planning.

Question 12

Which formula is more accurate, Mifflin-St Jeor or Harris-Benedict?

Accepted Answer

Mifflin-St Jeor is recommended by the American Dietetic Association as more accurate for modern populations.

Question 13

Why am I not losing weight at my calculated deficit?

Accepted Answer

TDEE calculators are estimates with 10-15% error. Track actual intake and weight for 2-3 weeks to calibrate your real TDEE.

Question 14

Does metabolism slow with age?

Accepted Answer

Yes, about 1-2% per decade after age 20, mainly due to muscle loss. Resistance training helps counteract this.

Question 15

Should I eat below my BMR?

Accepted Answer

Generally no. Eating below BMR long-term can cause muscle loss, nutrient deficiencies, and metabolic adaptation.

Question 16

What ratio of macros is best for weight loss?

Accepted Answer

Higher protein (35-40%) helps preserve muscle and increases satiety. The carb/fat split depends on your preference and tolerance.

Question 17

Do macros matter if I am in a calorie deficit?

Accepted Answer

Yes. Adequate protein (1.2-1.6 g/kg) prevents muscle loss. Higher protein also increases satiety.

Question 18

How do I know if my macros are right?

Accepted Answer

Track for 2-3 weeks. If energy, hunger, and weight trends are on track, your macros are working.

Question 19

What is the keto macro split?

Accepted Answer

Typically 5% carbs, 25-30% protein, 65-70% fat.

Question 20

Should I count net carbs or total carbs?

Accepted Answer

Total carbs for general health. Net carbs (total minus fiber) for strict keto.

Question 21

Is BMI accurate for muscular people?

Accepted Answer

No. BMI cannot distinguish between muscle and fat. Athletes often have "overweight" BMI with healthy body composition.

Question 22

What is a healthy BMI?

Accepted Answer

18.5-24.9 is the standard range, but BMI alone does not assess metabolic health.

Question 23

Is BMI or waist-to-height ratio better?

Accepted Answer

Waist-to-height ratio better predicts cardiovascular and metabolic risk because it measures fat distribution.

Question 24

Can you be metabolically unhealthy at a normal BMI?

Accepted Answer

Yes. About 30% of normal-weight adults have metabolic abnormalities like insulin resistance.

Question 25

Why do doctors still use BMI?

Accepted Answer

It is quick and free, but should be combined with waist measurement and lab work for individual assessment.

Question 26

What is a healthy waist-to-height ratio?

Accepted Answer

Below 0.5 — your waist should be less than half your height.

Question 27

Is waist-to-height ratio better than BMI?

Accepted Answer

Yes. A meta-analysis of 300,000 people found WHtR superior to BMI for detecting cardiometabolic risk.

Question 28

How do I measure my waist correctly?

Accepted Answer

At your navel, end of normal exhale, standing, directly on skin. Keep the tape horizontal.

Question 29

What causes a high waist-to-height ratio?

Accepted Answer

Excess visceral fat driven by diet, stress, genetics, inactivity, and poor sleep.

Question 30

Can I have a healthy BMI but unhealthy WHtR?

Accepted Answer

Yes. This is "normal weight central obesity" — normal BMI but excess abdominal fat with similar metabolic risks.

Question 31

How much protein do I need per day?

Accepted Answer

0.8 g/kg for general health, 1.6-2.2 g/kg for muscle building, 1.2-1.6 g/kg for fat loss, 1.2-1.5 g/kg for adults over 65.

Question 32

Can I eat too much protein?

Accepted Answer

For healthy kidneys, up to 2.2 g/kg is safe. Those with kidney disease should consult their doctor.

Question 33

Does protein timing matter?

Accepted Answer

Total daily intake matters most. But 20-30g per meal optimizes muscle protein synthesis.

Question 34

Is plant protein as good as animal protein?

Accepted Answer

Per gram, animal protein has a more complete amino acid profile. Combining plant sources achieves equivalent results.

Question 35

Why do older adults need more protein?

Accepted Answer

Anabolic resistance means aging muscles need stronger protein stimulus. 1.2-1.5 g/kg helps prevent sarcopenia.

Question 36

What does eGFR mean?

Accepted Answer

Estimated Glomerular Filtration Rate measures how well your kidneys filter waste. Normal is above 90 mL/min/1.73m².

Question 37

Can eGFR be temporarily low?

Accepted Answer

Yes. Dehydration, high-protein meals, intense exercise, and medications like NSAIDs can all temporarily lower eGFR.

Question 38

What is the 2021 CKD-EPI equation?

Accepted Answer

The updated race-free formula that is now the clinical standard for estimating kidney function.

Question 39

When should I see a nephrologist?

Accepted Answer

If eGFR is persistently below 60 on two tests 3 months apart, or if you have protein in your urine.

Question 40

Does creatine supplementation affect eGFR?

Accepted Answer

Yes. Creatine raises serum creatinine and can falsely lower eGFR by 5-15 points.

Question 41

What is ApoB and why does it matter?

Accepted Answer

ApoB counts atherogenic particles directly — a better predictor of cardiovascular risk than LDL cholesterol alone.

Question 42

What is a good TG/HDL ratio?

Accepted Answer

Below 2.0 is ideal. Above 3.5 suggests insulin resistance and small dense LDL particles.

Question 43

Can LDL be normal but ApoB be high?

Accepted Answer

Yes. This discordance means more small, dense particles than LDL-C suggests. ApoB is the better predictor.

Question 44

What is non-HDL cholesterol?

Accepted Answer

Total cholesterol minus HDL. It captures all atherogenic lipoproteins and is a good ApoB proxy.

Question 45

How often should I get a lipid panel?

Accepted Answer

Every 1-2 years if normal. Every 3-6 months if on treatment or values are abnormal.

Question 46

What is a normal ferritin level?

Accepted Answer

Males: 30-300 ng/mL. Females: 20-200 ng/mL. Optimal for energy is generally above 50-70 ng/mL.

Question 47

What does transferrin saturation tell you?

Accepted Answer

The percentage of iron-carrying protein loaded with iron. Below 20% suggests deficiency, above 45% suggests overload.

Question 48

Can ferritin be high without iron overload?

Accepted Answer

Yes. Ferritin rises with inflammation, infection, liver disease, and obesity.

Question 49

What are symptoms of iron deficiency before anemia?

Accepted Answer

Fatigue, hair loss, restless legs, brain fog, cold intolerance, and brittle nails.

Question 50

Should I take iron supplements if ferritin is low?

Accepted Answer

Discuss with your doctor first. The type, dose, and whether to investigate the cause all matter.

Question 51

What is a normal cortisol curve?

Accepted Answer

Cortisol peaks in the morning (6-8 AM) and declines through the day, reaching its lowest around midnight.

Question 52

What does a flat cortisol curve mean?

Accepted Answer

AM and PM levels are similar. Associated with chronic stress, burnout, and HPA axis dysregulation.

Question 53

Is adrenal fatigue real?

Accepted Answer

Not a recognized diagnosis, but HPA axis dysregulation producing abnormal cortisol patterns is well-documented.

Question 54

Which cortisol test is better, saliva or blood?

Accepted Answer

Saliva measures free cortisol with 4-point home collection. Blood measures total cortisol for diagnosing Cushing/Addison.

Question 55

What affects cortisol besides stress?

Accepted Answer

Sleep deprivation, shift work, alcohol, intense exercise, medications, caffeine, and eating patterns.

Question 56

How much vitamin D should I take daily?

Accepted Answer

It depends on your current level and body weight. Use our calculator for a personalized dose.

Question 57

Can you take too much vitamin D?

Accepted Answer

Yes. Levels above 100 ng/mL can cause toxicity. Retest 8-12 weeks after starting.

Question 58

What is the best form of vitamin D?

Accepted Answer

D3 (cholecalciferol) is better absorbed than D2. Take with a fat-containing meal.

Question 59

Why are so many people vitamin D deficient?

Accepted Answer

Indoor lifestyles, sunscreen, darker skin, obesity, and northern latitudes. Up to 42% of US adults are deficient.

Question 60

When should I retest vitamin D?

Accepted Answer

8-12 weeks after starting or changing dose. Every 6-12 months once at target.

Question 61

How long does caffeine stay in your system?

Accepted Answer

Half-life of 3-7 hours depending on CYP1A2 genetics. About 5 hours for normal metabolizers.

Question 62

What is a sleep-safe caffeine level?

Accepted Answer

Below 50 mg is generally considered unlikely to disrupt sleep architecture.

Question 63

How do I know if I am a slow metabolizer?

Accepted Answer

If one cup keeps you wired 8+ hours, you may have the slow CYP1A2 variant. 23andMe reports this.

Question 64

Does tolerance affect the half-life?

Accepted Answer

No. Tolerance changes how alert you feel but not how fast your liver clears caffeine.

Frequently Asked Questions

HOMA-IR Calculator

A1C Estimator

BMR & TDEE Calculator

Macro Calculator

BMI Calculator

Waist-to-Height Ratio

Protein Calculator

eGFR Calculator

Cholesterol & ApoB Risk

Iron & Ferritin Status

Cortisol Pattern Interpreter

Vitamin D Calculator

Caffeine Half-Life Calculator

Water Intake Calculator

Sleep Efficiency Calculator

Cycle Phase Estimator

Thyroid Dose Calculator