Academy · Articles
Scientific articles on lifestyle medicine
In-depth pieces from Dr Sergey Saadi on body biochemistry, nutrition, hormones and sleep — built on peer-reviewed research.
The hidden biochemistry of insulin resistance: why a standard blood-sugar test misleads
Most people assume that if their fasting glucose is normal (below 5.6 mmol/L), their carbohydrate metabolism is perfectly healthy. This is a dangerous myth. Type-2 diabetes and metabolic syndrome develop silently for 10–15 years before blood sugar ever starts rising.
ReadChronic low-grade inflammation — the invisible root cause of modern disease
Unlike acute inflammation (the body's normal defence against trauma or infection), systemic chronic inflammation is a silent destroyer. It causes no direct pain, but constantly drains the immune system and damages healthy tissues at the cellular level.
ReadChrono-nutrition and circadian rhythms: why meal timing decides your weight and sleep
Our body runs on a unique biological clock conducted by the suprachiasmatic nucleus (SCN) in the brain. But almost every cell and organ (liver, pancreas, gut) also has its own peripheral clock. The branch of science that studies the link between nutrition and these rhythms is called chrono-nutrition.
ReadSystemic low-grade inflammation and hs-CRP: the hidden metabolic killer
High-sensitivity C-reactive protein (hs-CRP) is one of the most important clinical windows into your body's invisible inflammatory process. Unlike acute inflammation it causes no pain, but it constantly damages the vascular endothelium, blocks insulin receptors and accelerates biological ageing.
ReadMuscle mass as a metabolic shield and glucose reservoir
Muscle is not just an organ of movement. It is the largest insulin-sensitive organ in the body and the main postprandial glucose buffer. Strength training opens a unique mechanism: activation of GLUT4 transporters independent of insulin.
ReadGut microbiome and the vagus nerve: the biochemistry of your second brain
The gut and brain do not just communicate through hormones — they are connected by a powerful two-way neural highway, the vagus nerve. Short-chain fatty acids (SCFAs) made by the microbiome are the chemical language of that conversation, regulating satiety, mood and systemic glucose control.
ReadSleep architecture and HRV: a mirror of the autonomic nervous system
Sleep is not homogeneous — it is a choreography of distinct phases, each with its own metabolic role. Morning heart rate variability (HRV) tells you precisely how well that choreography went and how resilient your autonomic nervous system is.
ReadHOMA-IR and the Kraft insulin test: seeing insulin resistance 10 years before diabetes
A normal fasting glucose is preserved until about 60% of pancreatic beta-cell function is already lost. If you want to see a metabolic problem before HbA1c climbs above 5.7%, there are two tools your physician should put next to your blood work: HOMA-IR and the Kraft insulin test.
ReadWhat is metabolic disease? Metabolic syndrome as one root cause of several diagnoses
"Metabolic disease" is not a single condition. It is a cluster of five related derangements that together define metabolic syndrome and ultimately produce type 2 diabetes, fatty liver, atherosclerosis and chronic fatigue. Roughly one in three Estonian adults meets the criteria — which usually means the core of metabolism, the action of insulin, has been failing quietly for years.
ReadInsulin resistance in women: PCOS, menopause and why the symptoms are not "just stress"
A woman's metabolism is not a smaller copy of a man's. Oestrogen, progesterone and the cycle itself influence insulin sensitivity significantly — and when something goes wrong, the earliest signs are cycle disruption, adult acne, hair growth, irritability and post-meal fatigue. That is why insulin resistance so often goes undiagnosed in women: the symptoms do not "look like diabetes".
ReadThe keto diet: what it is and what a 1-day keto menu actually looks like
The ketogenic diet is not a fad. It is a metabolic state in which the body runs on fat and ketone bodies rather than carbohydrate. Clinically we use it to lower insulin, treat epilepsy, drive metabolic remission and support weight loss — but only when it is timely for the person and built correctly.
ReadWhat is the keto diet? A doctor's plain-language explanation
The ketogenic diet is a very-low-carbohydrate way of eating in which the body switches from burning carbs to burning fat. Here is what actually happens in the body, who it fits and who should avoid it.
ReadKeto and alcohol: what you can drink and what to avoid
Alcohol does not automatically kick you out of ketosis, but it temporarily halts fat burning and makes hangovers much worse. Here is what is actually keto-friendly and what to avoid.
ReadMTHFR mutation: what it is and what it does to your health
MTHFR (methylenetetrahydrofolate reductase) is the enzyme that converts folate to its active 5-MTHF form. Two common variants — C677T and A1298C — can reduce enzyme activity by 30–70%. But the clinical meaning is more nuanced than internet forums claim.
ReadVitamin B12 deficiency: 9 symptoms doctors miss too often
B12 deficiency develops slowly — over two to five years. Symptoms are vague and are commonly blamed on stress, age or depression. Here are nine signs that should trigger a B12 check.
ReadMagnesium deficiency: symptoms, tests and which form to choose
About 50% of Europeans consume less magnesium than the recommended daily intake. Chronic subclinical deficiency is one of the most commonly undiagnosed metabolic problems — because serum magnesium only flags a deficiency once intracellular levels have already dropped substantially.
ReadCounting carbs: how to do it correctly
For weight loss, keto or diabetes management, it isn't enough to "eat fewer carbs" — you need to know how many net carbs you actually consume. Here is a practical guide without apps and without mistakes.
ReadKeto flu: why it happens and how to end it in 48 hours
"Keto flu" is a classic beginner problem: on days 2–5 you get headache, fatigue, irritability, muscle weakness and disturbed sleep. It is NOT flu and NOT a reaction to fat — it is electrolyte depletion, and it resolves within 24–48 hours with the right protocol.
ReadFasting insulin test in Estonia: price, where to take it, interpretation
Fasting insulin is one of the best early markers of metabolic risk, yet standard GP check-ups almost always leave it out. It costs 8–15 €, preparation is simple, but interpretation needs the right doctor.
ReadVitamin D blood levels: how much is good, how much is too little
Vitamin D status is measured as serum 25-hydroxy-D3 (25(OH)D). About 70–80% of people in Estonia are deficient in winter. But the "normal range" the lab prints doesn't equal "optimal".
ReadBelly fat: 6 real causes and which tests to take
Belly fat is two very different things — subcutaneous (harmless) and visceral, which surrounds internal organs and is one of the strongest predictors of cardiovascular disease. Visceral belly fat cannot be simply exercised off without addressing the metabolic cause.
ReadFerritin explained: what is an optimal level for energy and health
Ferritin reflects the body's iron stores — but the standard lab range (15–300 µg/L) means you can be deeply iron-deficient without anaemia while haemoglobin is still normal. Here is what a functionally optimal ferritin looks like, why it drops and when it is truly too high.
ReadLiver enzymes ALT and AST: how to actually read them
ALT and AST are the two most common liver enzymes on a blood panel. Standard lab ranges are wide (up to 45–50 U/L), but modern hepatology suggests that a healthy person's ALT should be considerably lower. Here is when a mildly elevated ALT deserves attention, what the AST/ALT ratio tells you, and how to read all of this in the context of metabolic-associated fatty liver (MASLD).
ReadInsulin resistance diet: Mediterranean vs low-carb vs keto — what actually works?
"Which diet should I choose for insulin resistance?" is one of the most common questions in my consultations. The Mediterranean, low-carb and ketogenic approaches all have solid evidence, but their mechanisms and long-term fit differ. Here is what the research says about who benefits from what.
ReadWhy isn't the scale moving? 6 hidden metabolic causes and a doctor's approach
The scale won't budge even though you're eating less and moving more? That doesn't always mean you're just not trying hard enough. Body energy balance is more complex than simple calorie subtraction. Here are six common but often overlooked metabolic causes.
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