7 min learnAug 26, 2026 02:11 PM IST
Arun, a 44-year-old govt, walked into the clinic holding an ultrasound report with a mix of confusion and disbelief. The scan, carried out for recurrent acidity, had proven fatty liver. “However I’m not fats,” he mentioned. He had a degree. His BMI (physique mass index) was 22.6 kg/m², inside the lean vary for an Asian grownup. He drank alcohol often and his liver enzymes had been mildly raised. By look, he appeared wholesome.
However his waist measured 93 cm, triglycerides had been elevated and HbA1c (common blood sugar rely of three months) was within the prediabetes vary. He had a desk job, ate beneficiant parts of rice and refined cereals, exercised irregularly and had comparatively little muscle. A fibrosis rating based mostly on routine blood checks was indeterminate. Liver elastography was subsequently suggested and confirmed larger stiffness than his look had prompt.
The analysis was lean metabolic dysfunction-associated steatotic liver illness (lean MASLD)—a reminder that thinness just isn’t the identical as metabolic well being.
Fatty liver with out weight problems
MASLD is the newer title for what was beforehand referred to as non-alcoholic fatty liver illness. It refers to liver fats occurring alongside at the very least one cardiometabolic abnormality, corresponding to excessive glucose, raised blood stress, elevated triglycerides, low HDL ldl cholesterol or extra adiposity. An individual doesn’t want to satisfy each criterion. Fatty liver accompanied by prediabetes or an elevated waist circumference could also be sufficient to put somebody inside the MASLD spectrum.
The definition of “lean” additionally varies with ethnicity. In Asian populations, lean MASLD usually refers to illness occurring at a BMI under 23 kg/m². This decrease cut-off issues in India as a result of South Asians typically develop diabetes and different metabolic issues at a decrease BMI than many Western populations. Arun was, subsequently, not an exception. He belonged to a bunch that may simply be missed as a result of fatty liver is usually related to extra physique weight.
What BMI fails to see
BMI measures weight relative to top nevertheless it doesn’t present the place fats is saved or how a lot muscle an individual has. Two folks with the identical BMI can have very completely different metabolic profiles.
When the physique’s capability to retailer fats safely below the pores and skin is exceeded, surplus fats can accumulate round stomach organs and inside the liver, pancreas and muscle. This visceral and ectopic fats triggers insulin resistance, irritation and the discharge of fatty acids into the liver. An individual could subsequently have slim legs and arms whereas carrying metabolically dangerous fats across the waist.
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In South Asians, a waist circumference of 90 cm or extra in males and 80 cm or extra in ladies suggests central adiposity. A waist-to-height ratio of about 0.5 is one other helpful warning signal. The weighing scale could stay unchanged whereas the waist slowly expands.
Low muscle mass provides to the issue. Skeletal muscle is a serious website for glucose disposal after meals. With much less muscle, glucose could also be cleared much less effectively, growing metabolic stress on the liver. This “thin-fat” or sarcopenic phenotype turns into extra vital with ageing, inactivity, insufficient protein consumption or repeated crash diets.
Greater than an incidental scan discovering
Fatty liver is typically handled as a innocent footnote on an ultrasound report. In some folks it stays simply that. In others, liver fats is accompanied by irritation, referred to as metabolic dysfunction-associated steatohepatitis (MASH). Over time, this could result in fibrosis, cirrhosis and, in a smaller proportion, liver most cancers. Lean sufferers will be identified late as a result of no person expects them to have metabolic liver illness. Regular or near-normal liver enzymes don’t reliably exclude important fibrosis. Lean MASLD is related to a better threat of liver-related issues. Its cardiovascular threat in contrast with obesity-associated MASLD stays below research, however being lean doesn’t shield in opposition to coronary heart illness. Blood stress, glucose, lipids, smoking and sleep apnoea nonetheless require consideration. Arun’s report couldn’t merely be dismissed with recommendation to “keep away from oily meals”.
Ask whether or not there’s fibrosis
When fatty liver is present in a lean particular person, measure waist circumference, blood stress, blood glucose, HbA1c, triglycerides and HDL ldl cholesterol. Alcohol consumption and medicines ought to be reviewed. Different causes of liver fats or irregular liver checks — together with viral hepatitis and chosen endocrine, autoimmune, dietary and inherited situations—ought to be thought of in response to the person historical past and examination.
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The following query just isn’t merely, “Is there fats within the liver?” It’s, “Has scarring begun?”
FIB-4 is a sensible first evaluation calculated from age, AST, ALT and platelet rely. A price under 1.3 usually signifies a low likelihood of superior fibrosis. Between 1.3 and a pair of.67, a second evaluation, often liver elastography, is really helpful. A price above 2.67 warrants specialist analysis. In adults over 65, a threshold of two.0 is mostly used to establish decrease threat. For Arun, the indeterminate FIB-4 consequence was exactly why evaluation didn’t cease with the ultrasound.
Don’t flip remedy right into a weight-loss contest
The standard recommendation to lose 7–10 per cent of physique weight could also be inappropriate for a lean particular person, notably when muscle mass is already low. The goal is to scale back visceral fats, enhance insulin sensitivity and protect or construct muscle. For an Indian weight loss program, this typically means decreasing parts of polished rice, refined flour, sweets, fruit juice and sugar-sweetened drinks somewhat than eliminating carbohydrates altogether. Greens, pulses and acceptable protein sources ought to occupy extra of the plate. Saturated fats and ultra-processed meals ought to be restricted. Alcohol ought to be minimised or averted relying on the scientific state of affairs.
Train ought to embody at the very least 150 minutes of cardio exercise every week together with resistance coaching on two or extra days. Strolling is effective, however it’s not a whole muscle-building programme. Energy coaching deserves to be a part of the prescription.
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Diabetes, prediabetes, hypertension and dyslipidaemia ought to be handled appropriately. Statins shouldn’t routinely be withheld as a result of liver enzymes are mildly raised; cardiovascular safety stays vital. Medicines ought to be individualised in response to fibrosis stage, diabetes, lipid profile, dietary standing and the danger of additional muscle loss.
Arun lowered refined-carbohydrate parts, added fibre-rich greens, pulses and protein, started supervised resistance train and acquired remedy for dyslipidemia. His weight modified little, however his waist, glucose management, energy and liver markers improved.
That’s the central lesson of lean MASLD: measure what BMI misses.
(Dr Bhattacharya is senior endocrinologist at Apollo Hospital, Delhi)
