People with anorexia nervosa frequently have elevated cholesterol despite eating very little, a finding that surprises many patients and clinicians alike. The primary driver is not that the body is making too much cholesterol but rather that it has slowed down the removal of cholesterol from the bloodstream, largely because of hormonal shifts triggered by severe fat loss. A meta-analysis pooling data from dozens of studies found that total cholesterol in acutely ill anorexia patients runs roughly 23 mg/dL higher than in healthy controls, with LDL cholesterol about 12 mg/dL higher.1PubMed Central. Increased lipid and lipoprotein concentrations in anorexia nervosa: a systematic review and meta-analysis The biology behind this paradox involves thyroid hormones, fat tissue breakdown, and the liver’s ability to pull cholesterol particles out of circulation.
How Common Is the Problem
High cholesterol in anorexia is not a fringe laboratory curiosity. In one study comparing patients with anorexia to non-anorexic controls, about 18% of the anorexia group had total cholesterol above 270 mg/dL, compared with only 5% of the control group. Total cholesterol, LDL, HDL, and a subfraction called HDL2 were all higher in the anorexia patients.2PubMed. Hypercholesterolaemia in anorexia nervosa: frequency and changes during refeeding Other research has confirmed that mean levels of total cholesterol, LDL, HDL, ketone bodies, and several apolipoproteins are all elevated in anorexia compared to healthy controls.3PubMed. Etiology of hypercholesterolemia in patients with anorexia nervosa So the pattern is consistent across studies: starvation raises, rather than lowers, blood lipids.
Why Cholesterol Rises When Calories Drop
The explanation centers on what happens to the liver when the body is severely malnourished. Cholesterol circulates in the blood inside lipoprotein particles, and the liver is responsible for pulling LDL particles back out of the blood through specialized receptors on its surface. In anorexia, this clearance process slows down considerably. The result is that LDL particles linger in the bloodstream longer than they should, driving up measured cholesterol levels.
Several interconnected factors cause that slowdown. When body fat stores are severely depleted, the body ramps up lipolysis, breaking down whatever fat remains and flooding the liver with free fatty acids. At the same time, thyroid hormone levels drop. The thyroid hormone T3, in particular, is a key regulator of the liver’s LDL receptors. Lower T3 means fewer active receptors on liver cells, which means less LDL gets pulled out of circulation. One case-control study concluded that elevated cholesterol in anorexia is primarily an LDL-driven phenomenon, determined by the severe loss of body fat and resulting thyroid hormone changes that reduce endogenous cholesterol production while simultaneously decreasing LDL removal from the blood.4PubMed. Lipoprotein metabolism in patients with anorexia nervosa: a case-control study investigating the mechanisms leading to hypercholesterolaemia
This is a critical distinction. The intuitive assumption might be that the body is somehow manufacturing excess cholesterol, but the opposite is closer to the truth. The body has actually dialed down its own cholesterol production. The problem is on the clearance side, not the production side.
The Body Is Not Overproducing Cholesterol
Research tracking a chemical marker of cholesterol synthesis called lathosterol helps clarify this point. In one study, lathosterol levels were relatively low at the start of treatment, when patients were most malnourished and their cholesterol was highest. As patients were refed over 30 days, lathosterol rose significantly, meaning the body’s own cholesterol-making machinery was actually ramping back up with nutrition. At the same time, apolipoprotein B, a protein that travels on LDL particles, dropped during refeeding. The patients with the highest initial cholesterol levels tended to be in the worst nutritional state, and the researchers concluded that high cholesterol in anorexia is not related to the body making too much cholesterol on its own.5PubMed. Plasma cholesterol and endogenous cholesterol synthesis during refeeding in anorexia nervosa
This matters because it undercuts the logic of treating the cholesterol with dietary changes. A patient who is already barely eating is not going to benefit from being told to eat less saturated fat. The cholesterol is high because the body cannot clear it efficiently, not because of what is being consumed.
Which Cholesterol Fractions Are Affected
The meta-analysis mentioned earlier found that virtually every lipid fraction was elevated in acutely ill anorexia patients: total cholesterol, LDL, HDL, triglycerides, and apolipoprotein B were all significantly higher than in healthy controls.1PubMed Central. Increased lipid and lipoprotein concentrations in anorexia nervosa: a systematic review and meta-analysis But the picture is more nuanced than just “everything goes up.”
More recent metabolomic work has identified which specific particle sizes are responsible. Patients with acute anorexia show elevated concentrations of small, dense LDL particles and large HDL particles compared to healthy controls.6PubMed. Perturbations in plasma amino acid and lipoprotein subfraction profiles in anorexia nervosa before and after refeeding: A metabolomic cross-sectional and longitudinal analysis Small, dense LDL is generally considered the more harmful type because these particles penetrate artery walls more easily. Separate research found that very-low-density lipoprotein (VLDL) and small LDL particles were specifically increased in anorexia, and that VLDL levels correlated with the activity of cholesteryl ester transfer protein, an enzyme involved in swapping lipids between different lipoprotein particles. The researchers described this as a shift toward a more atherogenic lipoprotein profile.7PubMed Central. Anorexia Nervosa Is Associated with a Shift to Pro-Atherogenic Low-Density Lipoprotein Subclasses
So it is not just that total numbers are higher. The composition of the lipoprotein particles themselves tilts in a potentially riskier direction during active illness.
What Happens When Patients Start Eating Again
The trajectory of cholesterol during refeeding is not straightforward. In some studies, total cholesterol stays roughly stable or even rises further in the early weeks of weight restoration before eventually normalizing. The meta-analysis data showed that partially weight-restored patients still had total cholesterol about 15 mg/dL above controls and LDL about 19 mg/dL above controls, meaning the lipid disturbance does not resolve immediately with nutritional rehabilitation.1PubMed Central. Increased lipid and lipoprotein concentrations in anorexia nervosa: a systematic review and meta-analysis
One study of adolescents tracked lipid changes through weight restoration and found an interesting pattern. Total cholesterol was not dramatically different from controls at admission or discharge, but the lipid profile shifted in notable ways: triglycerides actually dropped with treatment and were lower than controls at discharge, while HDL and its main structural protein, apolipoprotein A1, rose significantly with weight gain and ended up higher than in controls. LDL did not change much, but apolipoprotein B was elevated at discharge.8Journal of Adolescent Health Care. Effect of weight restoration on the dyslipoproteinemia of anorexia nervosa The researchers described this as a dyslipoproteinemia characterized by high HDL and low triglycerides, a pattern that was actually accentuated by restoring body weight. In other words, the lipid abnormalities did not simply snap back to normal with refeeding; some got more pronounced before they eventually resolved.
For clinicians managing recovery, this means a cholesterol test taken a few weeks into refeeding may look worse than expected. That does not mean treatment is failing. It is a transient metabolic readjustment, and cholesterol levels generally normalize as patients approach a healthy weight and their hormonal balance restores.
The Adolescent and Menstrual Connection
In adolescents with eating disorders, cholesterol levels are closely tied to reproductive hormone status. A study of girls with eating disorders and weight loss found that those who had not yet reached menarche or who had lost their periods were far more likely to have elevated cholesterol than those still menstruating. About 38% of premenarcheal girls had total cholesterol above 5.0 mmol/L, compared with 32% of girls with secondary amenorrhea and only 17% of girls who still had regular periods.9PubMed Central. Plasma cholesterol is related to menstrual status in adolescent girls with eating disorders and weight loss
Cholesterol levels in the amenorrheic girls were inversely related to estradiol and T3 levels, reinforcing the hormonal mechanism described earlier. Less estrogen and less thyroid hormone meant higher cholesterol. In girls who were still menstruating, the relationships were different: cholesterol tracked positively with BMI and inversely with weight loss and T3. This suggests that the hormonal disruption of losing one’s period is a stronger driver of cholesterol elevation than weight loss alone, though both contribute.
For parents and pediatricians, a high cholesterol reading in a teenager with an eating disorder should prompt concern about the severity of the illness and hormonal disruption, not a referral to a dietitian for heart-healthy eating. The cholesterol problem will resolve when the eating disorder does.
Does the High Cholesterol Actually Damage the Heart
This is the question that worries patients and families most. In the general population, elevated LDL cholesterol is one of the strongest risk factors for atherosclerosis. Does anorexia-related hypercholesterolemia carry the same cardiovascular danger?
The evidence so far suggests it probably does not, at least not in the short to medium term. One study measured carotid artery intima-media thickness, a reliable indicator of early atherosclerosis, in anorexia patients and found no difference compared to healthy controls. Because carotid thickness correlates strongly with coronary atherosclerosis, the researchers concluded that chest pain in anorexia patients is unlikely to have an atherosclerotic origin.10International Journal of Eating Disorders. Coronary atherosclerosis in anorexia nervosa
That said, the finding of a shift toward small, dense LDL and elevated VLDL particles in anorexia does raise theoretical concerns about long-term vascular health, especially in people who cycle in and out of the illness over many years.7PubMed Central. Anorexia Nervosa Is Associated with a Shift to Pro-Atherogenic Low-Density Lipoprotein Subclasses The honest answer is that we do not have good long-term data on whether decades of intermittent anorexia-related hypercholesterolemia translate into higher cardiovascular event rates. Most cardiovascular research in anorexia has focused on arrhythmias, heart muscle wasting, and sudden cardiac death, which are the more immediate threats. The cholesterol question remains somewhat open for the chronic, relapsing-remitting course many patients experience.
What is clear is that prescribing statins to an acutely malnourished anorexia patient would be inappropriate. The cholesterol elevation is a symptom of starvation, not an independent disease. Statins work by suppressing the liver’s cholesterol production, but as the lathosterol data showed, production is already suppressed in anorexia. Adding a statin on top of that would be treating a lab number without addressing its cause, and could potentially worsen liver function in someone already metabolically fragile.
Bile Acids and the Gut Microbiome
An emerging area of research connects anorexia-related cholesterol changes to the gut. Cholesterol is a building block for bile acids, which the liver produces and secretes into the intestines to help digest fat. Normally, bile acids are recycled efficiently through intestinal reabsorption, but changes in gut bacteria can alter how bile acids are processed.
A study published in Nature Microbiology found that patients with anorexia had elevated blood levels of both primary bile acids like cholic acid and glycocholic acid, and secondary bile acids such as ursodeoxycholic acid and several others. Secondary bile acids are produced by gut bacteria, and their elevation suggests that the altered microbiome in anorexia is actively changing bile acid metabolism.11Nature Microbiology. The gut microbiota contributes to the pathogenesis of anorexia nervosa in humans and mice The same study found elevated tryptophan metabolites produced by gut microbes, which are involved in appetite and satiety signaling.
How does this connect to cholesterol? Bile acid metabolism and cholesterol metabolism are tightly linked. When bile acids are not recycled normally, the liver has to pull more cholesterol from circulation to make new bile acids, or conversely, when bile acid signaling is disrupted, the feedback loops that regulate cholesterol clearance can malfunction. The precise contribution of gut microbial changes to the hypercholesterolemia of anorexia is still being worked out, but it adds another layer to the story beyond the thyroid-and-clearance model.
The Bone Marrow Fat Paradox
The cholesterol anomaly in anorexia is part of a broader pattern where fat behaves in unexpected ways during starvation. One of the strangest findings is that while subcutaneous and visceral fat are drastically depleted in anorexia, bone marrow fat actually increases. Women with anorexia have significantly higher marrow fat at both the lumbar spine and the femur compared to healthy-weight controls.12PubMed Central. Increased bone marrow fat in anorexia nervosa This marrow fat accumulation correlates inversely with bone mineral density, suggesting it may contribute to the high fracture risk seen in anorexia.
Follow-up research confirmed that the total amount of marrow fat is higher in anorexia, though the composition of the fat, meaning the specific types of fatty acids, is similar to that of normal-weight controls.13PubMed Central. Marrow fat composition in anorexia nervosa The paradox of fat accumulating in bone marrow while disappearing everywhere else raises questions about how the body redistributes lipids under extreme starvation. It also underscores that the metabolic disturbances in anorexia are not a simple story of depletion across the board. Fat and cholesterol get rerouted in ways that are still not fully understood, and that rerouting has real consequences for bone health, cardiovascular risk, and recovery trajectories.
For clinicians, these findings are a reminder that standard lab panels and body composition assumptions do not translate neatly to the metabolic reality of anorexia. A patient who looks severely underweight may have a cholesterol panel that resembles someone eating a high-fat Western diet, and may have bone marrow that is fattier than normal despite having almost no visible body fat. The body in starvation follows its own metabolic logic, and that logic does not align with the rules of thumb used for well-nourished patients.