on October 15, 2026
Ketosis: a metabolic adaptation, not a shortcut to health
The ketogenic diet is based on a drastic reduction in carbohydrate intake, combined with a high proportion of fat and generally controlled protein intake. The reduction in carbohydrates leads to a decrease in glucose and insulin availability and promotes the use of fatty acids as an energy source.
The liver converts some of the fatty acids into ketone bodies, mainly beta-hydroxybutyrate, acetoacetate, and acetone. These molecules can be used by various tissues as an energy substrate.
It is a physiological adaptation mechanism that also occurs during prolonged fasting. However, its existence does not mean that a state of ketosis is automatically beneficial for everyone.
This is the first principle to remember when talking about the ketogenic diet: a physiological metabolic mechanism is not necessarily equivalent to a universally safe dietary strategy.
Nutritional ketosis must also be distinguished from diabetic ketoacidosis, a pathological condition characterized by excessive ketone body production and an altered acid-base balance.
Why the ketogenic diet causes weight loss
The weight loss observed with ketogenic diets is real, especially in the short and medium term. The mechanisms are multiple.
The drastic reduction in carbohydrates initially leads to a loss of glycogen and associated water. Subsequently, energy restriction, increased fat oxidation, spontaneous reduction in calorie intake, and, in some individuals, increased satiety may promote a reduction in body mass.
Clinical studies have documented that low-carbohydrate diets can produce significant weight loss. However, the advantage compared to other dietary models tends to decrease over time and depends mainly on the ability to maintain an appropriate diet over time.
A review of randomized trials on 14 different dietary programs, including over 21,000 participants, showed that after six months, low-carbohydrate and low-fat diets resulted in a weight loss of overall similar magnitude.
Weight loss, therefore, does not prove that ketogenic is necessarily superior for health in the long term.
The possible benefits: real, but to be contextualized
The ketogenic diet can have specific clinical applications and, in selected patients, can produce favorable metabolic effects.
Among the most frequently observed results are:
· reduction in body weight;
· decrease in triglycerides;
· improvement in some glycemic parameters in individuals with insulin resistance or type 2 diabetes;
· reduction in appetite in some individuals;
· improvement in some metabolic parameters associated with obesity.
A recent meta-analysis from 2026, including 62 randomized studies, confirmed a significant reduction in triglycerides, but also highlighted an average increase in LDL cholesterol and total cholesterol.
This point is fundamental.
It is incorrect to present the ketogenic diet as a model in which metabolic benefits automatically cancel out possible cardiovascular risks.
Furthermore, the lipid response is not the same in everyone. A meta-analysis of randomized studies showed that in normal-weight individuals, very low-carbohydrate diets can lead to particularly significant increases in total and LDL cholesterol.
The LDL cholesterol problem
One of the most delicate aspects concerns the lipid profile itself.
The reduction in triglycerides may appear favorable, but it must not lead to overlooking a possible increase in LDL cholesterol.
A 2026 review and meta-regression of 53 randomized studies found a reduction in triglycerides of approximately 22 mg/dL, but also an increase in LDL of approximately 8.2 mg/dL and in total cholesterol of approximately 8.1 mg/dL. The authors emphasize the uncertainty regarding long-term cardiovascular effects.
The result is therefore far from unequivocal.
A diet that improves some biomarkers and worsens others cannot be automatically considered cardioprotective.
The composition of fats takes on decisive importance. A ketogenic diet built predominantly around extra virgin olive oil, fish, nuts, and seeds is metabolically very different from a diet rich in butter, processed meats, fatty cheeses, and other foods high in saturated fats.
Cardiovascular risk cannot be assessed by a single parameter
The cardiovascular system does not respond to a single food or a single laboratory value.
Blood pressure, LDL, triglycerides, HDL, blood glucose, insulin resistance, inflammation, kidney function, body composition, physical activity, and overall dietary quality all contribute to determining risk.
For this reason, the idea that entering ketosis automatically means "burning fat and protecting the heart" is an oversimplification.
The literature on low-carbohydrate diets actually shows a complex picture: weight loss and triglyceride improvement may be accompanied by an increase in LDL.
The risks of the ketogenic diet: the most often underestimated aspect
The media success of the ketogenic diet has often emphasized weight loss, while less attention is paid to its physiological complexity.
A highly restrictive diet can cause:
fatigue, headache, nausea, dizziness, constipation, gastrointestinal alterations, halitosis, weakness, a feeling of "brain fog", dehydration, and electrolyte imbalances.
These disturbances are particularly frequent in the initial phase, when the body adapts to the drastic reduction in carbohydrates.
A systematic review published in 2026, including 36 studies and 42 ketogenic interventions, found at least one adverse event in 43% of participants. The frequency varied considerably depending on the type of diet, the population studied, and the condition treated.
The so-called "keto flu", or ketogenic flu, is therefore not simply a commercial invention: it represents the set of symptoms that can appear during adaptation to carbohydrate restriction.
Kidney stones: a documented risk
The ketogenic diet can alter the acid-base balance, uric acid metabolism, calcium and citrate excretion, and water balance.
This can promote the formation of kidney stones in predisposed individuals.
A systematic review and meta-analysis including 36 studies and 2,795 people estimated an overall incidence of kidney stones of approximately 5.9%, with an estimate around 7.9% in adults. Uric acid stones were found to be among the most frequent.
This data takes on particular relevance when the diet is followed for prolonged periods or in people who already have kidney vulnerability.
Contraindications: when ketogenic should not be improvised
The most important principle is simple:
THE KETOGENIC DIET SHOULD NOT BE STARTED ON YOUR OWN.
Its composition must be defined based on clinical conditions, nutritional status, age, body composition, pharmacological therapy, and any risk factors.
Particular caution or exclusion of the ketogenic approach for weight loss purposes is necessary in the presence of:
· pregnancy;
· breastfeeding;
· childhood and adolescence, unless specifically indicated by specialists;
· kidney failure;
· liver failure;
· heart failure or other conditions requiring particular control of fluids and electrolytes;
· type 1 diabetes;
· eating disorders or certain psychiatric conditions;
· alcohol abuse or dependence;
· lipid metabolism disorders;
· metabolic or genetic conditions in which fat or ketosis management is problematic.
It is important to clarify that the ketogenic diet also has specialized therapeutic indications, especially for certain forms of drug-resistant epilepsy. This does not mean, however, that a ketogenic diet used in a specialized neurological setting can be automatically transferred to the general population as a weight-loss diet.
Type 1 diabetes: a situation that requires particular caution
In type 1 diabetes, the problem takes on a completely different dimension.
The presence of insufficient insulin, associated with a strong restriction of carbohydrates, can increase the production of ketone bodies. The most important risk is that of confusing nutritional ketosis with a condition that can evolve into diabetic ketoacidosis.
The most recent literature confirms that low-carbohydrate diets can favorably alter some glycemic parameters in people with type 1 diabetes, but also emphasizes the need for careful clinical assessment and ketone monitoring.
A specific review has also highlighted concerns related to diabetic ketoacidosis, hypoglycemia, and dyslipidemia, especially when the diet is adopted without adequate control.
Therefore, type 1 diabetes is not the ground on which to independently experiment with a ketogenic diet.
Pregnancy: it is not the time to experiment with ketosis
Pregnancy represents a physiological condition characterized by particular nutritional needs.
The fetus needs an adequate supply of energy and essential nutrients for growth and neurological development. An extreme dietary restriction should not be adopted for weight-loss purposes during pregnancy.
Even when the goal is weight control, the priority must be nutritional completeness, not the induction of ketosis.
Pregnancy and breastfeeding therefore require specific nutritional planning and are not conditions in which ketogenic regimens should be used independently.
Childhood and adolescence: growth before weight loss
Children and adolescents are not simply "smaller adults".
They are growing organisms in which energy, proteins, essential fatty acids, vitamins, and minerals must support skeletal, muscular, neurological, and hormonal development.
The ketogenic diet can be used in childhood in particular neurological conditions and only within specialized clinical protocols. It must not be confused with a do-it-yourself weight-loss diet.
For an overweight adolescent, the goal should be above all to improve the quality of nutrition, physical activity, sleep, eating behavior, and relationship with food.
Extreme restriction can impoverish the quality of the diet
Eliminating or drastically reducing entire categories of foods also means reducing some important sources of nutrients and fiber.
The strong limitation of whole grains, legumes, and fruit can reduce the intake of:
· dietary fiber;
· some vitamins;
· minerals;
· polyphenols;
· plant bioactive compounds;
· substrates useful for the intestinal microbiota.
However, this means that the ketogenic diet is not a simple diet.
It requires precise nutritional planning, monitoring of intake, and, when indicated, targeted supplementation.
Why "do-it-yourself" is particularly risky
One of the most common mistakes is thinking that "ketogenic" simply means:
eating more fat and cutting out bread and pasta.
It is not like that.
The clinical ketogenic diet is a structured nutritional intervention, in which total energy, the quantity and quality of fats, protein intake, carbohydrates, fiber, micronutrients, hydration, and electrolytes must be considered.
The ratio between macronutrients can also change depending on the specific protocol.
For this reason, it is not correct to turn a clinical diet into a generic list of "allowed" and "forbidden" foods.
The ketogenic diet should be prescribed and monitored by qualified professionals, especially when used for therapeutic purposes or in the presence of diseases.
Hypertension: you do not need to enter ketosis to improve blood pressure
Hypertension represents one of the main modifiable risk factors for heart attack, stroke, heart failure, and kidney disease.
Nutritional intervention is essential, but it is not necessary to resort to extreme carbohydrate restriction.
A much more physiological strategy consists in improving the overall quality of nutrition, increasing the consumption of plant-based foods, fruit, legumes, and whole grains, and reducing ultra-processed foods, excess sodium, and foods rich in saturated fats.
The World Health Organization recommends for adults a sodium intake of less than 2 g per day, equivalent to less than 5 g of salt per day, and emphasizes the importance of increasing potassium through food.
The Biomolecular Diet: nourishing metabolism without extremes
A dietary approach oriented toward metabolic health does not necessarily have to involve the drastic elimination of carbohydrates.
The Biomolecular Diet, in the model proposed by Moltitudo, places the quality of foods, nutritional density, and the relationship between nutrition, metabolism, inflammation, and longevity at its center.
The principle is not "eat fewer categories of foods", but choose foods better and build a nutritional balance that is sustainable over time.
In this sense, the approach is close to the principles of the Mediterranean diet and the Longevity Diet: an abundance of plant-based foods, legumes, whole grains, fruit, vegetables, nuts and seeds, extra virgin olive oil, adequate sources of plant proteins, and limited consumption of foods of animal origin.
The goal is to provide the body with a multitude of micronutrients and bioactive molecules through dietary variety.
Hypertension: the plate can become a prevention tool
A diet favorable to blood pressure should favor:
vegetables and greens, for fiber, potassium, magnesium, folates, and phytochemical compounds;
fruit, in quantities compatible with individual energy needs;
legumes, important sources of fiber, plant proteins, potassium, and magnesium;
whole grains, which allow for a higher intake of fiber and micronutrients compared to refined products;
fish, especially oily fish, as a source of omega-3 fatty acids;
vegetable oils (olive, evening primrose, borage, flaxseed, cumin), rich in monounsaturated fatty acids and phenolic compounds;
nuts and seeds, in adequate quantities;
spices, aromatic herbs, and naturally flavorful foods, usable to reduce the use of salt.
Conversely, ultra-processed foods, processed meats, salty snacks, industrial sauces, and hidden sources of sodium must be eliminated.
The evidence on the Mediterranean diet and blood pressure
The superiority of a balanced diet is not merely theoretical.
A meta-analysis of 35 randomized studies and almost 14,000 participants found a reduction in systolic and diastolic blood pressure associated with the Mediterranean diet compared to the usual diet.
Even more interesting is a randomized trial that compared the Mediterranean diet and DASH in people with normal-high blood pressure or grade 1 hypertension, both associated with salt restriction. The Mediterranean diet produced a greater reduction in ambulatory systolic blood pressure compared to the control, while both the Mediterranean diet and DASH showed favorable effects on blood pressure.
Even comparative reviews of dietary strategies place DASH and the Mediterranean diet among the effective approaches for blood pressure.
Hidden salt: a more important target than the demonization of carbohydrates
For cardiovascular health, it is often more important to ask where carbohydrates and fats come from than to eliminate them indiscriminately.
A whole grain is not equivalent to an ultra-processed baked product.
A legume is not equivalent to a refined snack.
A fruit is not equivalent to a sugary drink.
Extra virgin olive oil is not equivalent to an industrial fat.
The quality of the food matrix is decisive.
Likewise, reducing salt does not simply mean removing salt from the salt shaker: a significant part of dietary sodium actually comes from packaged products, cheeses, processed meats, sauces, broth cubes, and snacks.
The real question is not "does the ketogenic diet work?"
The scientifically more correct question is:
for whom, for what goal, for how long, and with what medical supervision?
For a subject with obesity and specific metabolic alterations, a low-carbohydrate or ketogenic diet can represent one of the available tools.
For another person, it may be poorly indicated.
In a normoweight subject with a predisposition to hypercholesterolemia, the increase in LDL can represent a concrete problem. A meta-analysis of randomized trials observed, in normoweight subjects, an average increase in LDL of about 1.08 mmol/L, equivalent to about 42 mg/dL, along with an increase in total cholesterol and apolipoprotein B.
In a person with type 1 diabetes, the problem may instead be the control of ketosis and the risk of metabolic complications.
In a patient with kidney disease, the management of fluids, electrolytes, and metabolism may require even greater caution.
During pregnancy or growth, the priority is to ensure a complete nutritional intake.
The same diet cannot therefore be considered suitable for everyone.
Losing weight does not necessarily mean becoming healthier
Body weight is an important parameter, but it does not represent health status on its own.
A nutritional strategy should simultaneously improve:
· body composition;
· blood pressure;
· glucose metabolism;
· lipid profile;
· cardiovascular function;
· gut health;
· micronutrient intake;
· muscle mass;
· sleep quality;
· psychological relationship with food;
· ability to maintain results over the long term.
If a diet allows for weight loss but simultaneously causes a significant worsening of other clinical parameters, the result must be interpreted with caution.
A long-term strategy: variety, balance and personalization
Preventive nutrition should not be built on the search for the "perfect" diet, but on the ability to create a sustainable, varied and metabolically coherent diet based on individual characteristics.
This is where the Biomolecular Diet can offer a different perspective from simple restriction.
Do not eliminate by principle, but choose.
Do not demonize a macronutrient, but assess its quality, quantity and context.
Do not pursue ketosis as an end in itself, but work on the conditions that promote a healthy metabolism.
Do not seek extremely rapid results, but build dietary behaviors capable of supporting the person over time.
The fundamental message: no to do-it-yourself
The ketogenic diet should not be considered a simple fad diet.
It is a nutritional intervention that profoundly alters energy metabolism and, for this very reason, can produce both favorable effects and undesirable consequences.
The possible benefits for weight and certain metabolic parameters must not overshadow the risks: increased LDL in some individuals, possible formation of kidney stones, gastrointestinal disorders, dehydration, electrolyte imbalances and, in vulnerable people, more serious metabolic complications.
The risk increases when the diet is prolonged without supervision, designed in an unbalanced way, or applied to people who have contraindications.
For this reason, the principle must be categorical:
NO TO DO-IT-YOURSELF.
A ketogenic diet, when truly indicated, must be prescribed and supervised by qualified professionals, with clinical assessment and monitoring of the necessary parameters.
For most people who simply wish to improve their metabolic health, blood pressure and dietary quality, there is no need to resort to extreme restriction.
A Biomolecular Diet inspired by the principles of the Mediterranean diet and the Longevity Diet, rich in plant-based foods, legumes, whole grains, fruit, fish, extra virgin olive oil, nuts and minimally processed foods, offers a more balanced, varied and sustainable strategy.
Health does not come from depriving yourself of a single category of nutrients.
It comes from an overall balance between diet, movement, body composition, metabolism, sleep and lifestyle.
Bibliographic references
1. The Impact of the Ketogenic Diet on the Lipid Profile in Adults: A Comprehensive Review and Meta-Regression Analysis of Randomized Controlled Trials. Endocrine Practice, 2026. DOI: 10.1016/j.eprac.2026.01.009.
2. Ketogenic diet-induced changes in adult lipid metabolism: a comprehensive systematic review and meta-regression of randomized controlled trials. BMC Cardiovascular Disorders, 2026. DOI: 10.1186/s12872-026-05799-5.
3. Adverse events and tolerability of ketogenic diets – a systematic literature analysis. BMC Nutrition, 2026.
4. Increased low-density lipoprotein cholesterol on a low-carbohydrate diet in adults with normal but not high body weight: A meta-analysis. American Journal of Clinical Nutrition, 2024.
5. Effects of very low-carbohydrate ketogenic diets on lipid profiles in normal-weight adults: a meta-analysis. Nutrition Reviews, 2023. DOI: 10.1093/nutrit/nuad017.
6. Incidence and Characteristics of Kidney Stones in Patients on Ketogenic Diet: A Systematic Review and Meta-Analysis. 2021.
7. Low-Carb and Ketogenic Diets in Type 1 Diabetes: Efficacy and Safety Concerns. 2025.
8. Ketogenic diets in the management of type 1 diabetes: Safe or safety concern? Cleveland Clinic Journal of Medicine, 2021. DOI: 10.3949/ccjm.88a.20121.
9. Mediterranean diet and blood pressure reduction in adults with and without hypertension: A systematic review and meta-analysis of randomized controlled trials. Clinical Nutrition, 2021. DOI: 10.1016/j.clnu.2021.01.030.
10. DASH vs. Mediterranean diet on a salt restriction background in adults with high normal blood pressure or grade 1 hypertension: A randomized controlled trial. Clinical Nutrition, 2023. DOI: 10.1016/j.clnu.2023.08.011.
11. Comparative effects of different dietary approaches on blood pressure in hypertensive and pre-hypertensive patients: A systematic review and network meta-analysis. 2018.
12. World Health Organization. Healthy diet. Guidelines on sodium, potassium, fruit and vegetables.
13. World Health Organization. Reducing sodium intake to reduce blood pressure and risk of cardiovascular diseases in adults. Recommendation: less than 2 g of sodium/day, equivalent to less than 5 g of salt/day.
