In Feeding Evolutionary, my first book published two years ago, defended a nutritional approach that is consistent with our history as a species: a diet based on natural foods, low in carbohydrates, combined with fasting intermittent. A pattern very different from the present, that pushes us to eat between three and five times a day products ultraprocesados: loaded with calories, but empty of nutrients. Refined flours, sugars, vegetable oils, seeds, additives and a mixture unnatural of macronutrients —carbohydrates with fats— designed for one thing: to make us eat more.
What I wrote in 2023 is based on the best scientific evidence available at the time, which was already solid. But since then have appeared, new studies not only confirm what we knew, but that further reinforce this approach. And worth sharing.
Let’s start at the beginning.
What are the intermittent fasting (TRE) and the low-carb diet?
The intermittent fasting is not a diet but rather an eating pattern that alternates periods of eating with periods of fasting. There are several modes, but one of the most well-known is the restricted feeding time, or Time-Restricted Eating (TRE) in English.
As its name suggests, consists of concentrating all meals of the day in a reduced time frame, usually of 8 hours, and do not consume calories during the 16 remaining hours, including sleep. That is to say, divided the day into three blocks of eight hours: one to feed, and two for fasting. A practical example: end-dinner at 21:00 and did not return to ingest any calories until 13:00 of the following day, allowing only calorie-free beverages like water, coffee or tea.
On the other hand, a low-carb diet involves reducing (not completely eliminate) the consumption of foods rich in carbohydrates that have arrived more recently in our evolution with agriculture: cereals, tubers and legumes. In addition, try to avoid industrial products —not food— even more recent, and with a content much higher carbohydrate, by being made from refined flours and sugars.
To evaluate our evolutionary adaptation to these foods, let’s do some simple calculations. If we take as a reference the 300,000 years of existence of the Homo sapiens, during which our nutritional needs, and physiology have remained relatively stable, these are the percentages of time that we have lived with carbohydrate-rich foods:
- Agriculture in the Neolithic (~10,000 years): 3,3 % of the time.
- Products ultraprocesados industrial (~75 years): 0,025 % of the time.
The more recent has been the incorporation of a food, the lower has been evolutionary pressure to adapt to it. That’s why, although there is some adaptation to agricultural products, the ultraprocesados are a novelty so recent that we have not had the evolutionary time sufficient to develop mechanisms of adaptation are significant.
General benefits of intermittent fasting
When I wrote the Power Evolutionary, the scientific literature on intermittent fasting was already overwhelming. However, in the book I decided to focus on a single study key, published in December 2019 in the New England Journal of Medicine, signed by Rafael de Cabo and Mark Mattson, National Institute on Aging of EE. UU. and the Johns Hopkins University. This study summarised the available scientific evidence up to the time, and these were observed benefits of intermittent fasting:
At the cellular level:
- Resistance to oxidative stress: activates an adaptive response that reinforces the antioxidant defenses, DNA repair, and mitochondrial function.
- Autophagy: it stimulates the removal and recycling of molecules damaged, which contributes to the cleaning cell and the reduction of inflammation.
- Brain: improves function and increases resistance to damage.
General health and ageing:
- Improvement in both the total life expectancy such as life expectancy, disease-free (but still relevant).
Physical and cognitive functions:
- Increase the strength, the balance , and coordination.
- Promotes fat losswhile maintaining muscle mass (especially with fasts for 16 h).
- Improves the function cognitive: memory, space, working, and associative.
- Reduces neuroinflammation.
Metabolic diseases:
- Decreases the body fat and insulin resistance.
- Improves the control of type 2 diabetes and obesity.
Cardiovascular health:
- Decreases blood pressure, heart rate, cholesterol, triglycerides and glucose.
- Reduces the inflammation and oxidative stressas key factors in atherosclerosis.
- Increases the neurotransmitter GABA and the variability of the heart rate, favoring the dominance of the parasympathetic nervous system.
Cancer:
- Diminishes the appearance of tumors miscarriage.
- Inhibits the growth of various types of tumors.
- Improves the effectiveness of chemotherapy and radiation therapy.
- Protects healthy cells, negatively affecting only the energy metabolism of cancer cells.
Neurodegenerative diseases:
- Slows the progression of alzheimer’s disease and the párkinson.
- Strengthens the resistance of neuronal stress, activating autophagy, neurotrophic factors, and DNA repair.
Asthma:
- Reduces respiratory symptoms and air resistance.
Multiple sclerosis:
- Fasting on alternate days, or for three consecutive days reduced demyelination, autoimmune and improves both symptoms and motor functions in just two months.
Rheumatoid arthritis:
- Reduces inflammation, generating functional improvements.
Injury by ischemia or operations:
- A previous fasting reduces the tissue damage and inflammation, improving postoperative recovery.
Fasting combined with a diet low in carbohydrates: new studies.
Benefits for metabolic health (weight and diabetes)
In a clinical trial recently published in 2022, a group of researchers examined the effects of combining a diet restricted in time (intermittent fasting 8 hours) with a low-carbohydrate diet on people with metabolic syndrome. The results were very clear: the combination of both approaches was more effective than apply each one separately.
The study, which was carried out during three months, the participants change their physical activity, showed significant improvement in weight, abdominal fat, glucose, lipids and other markers key.
Below is a summary of the benefits observed:
Changes and body composition:
- Loss of total body weight (5 kg on average), higher than with the fasting or the diet separately.
- Reduction of visceral fat (the most dangerous for health).
- Reduction of the subcutaneous fat.
- Decreased total body fat, without losing muscle mass.
- Reduction of the circumference of the waist and hip.
- Improvement of body mass index (BMI).
Glucose metabolism:
- Reduction of the glucose on an empty stomach.
- Decrease in the glycosylated hemoglobin (HbA1c).
- Lower levels of insulin in the fasted state, which indicates less of a burden pancreatic.
- Improvement of insulin sensitivity (the body responds better to it).
Other markers of metabolic:
- Decrease uric acid, related to insulin resistance and risk of gout.
- Significant reduction of triglycerides in the blood.
- Increase HDL cholesterol.
- Improvement of the ratio triglycerides / HDL, a key marker of cardiovascular risk.
Blood pressure and tolerance:
- Reduction of the blood pressure diastolic blood pressure without adversely affecting the systolic.
- General improvement of the profile cardiometabolic, without the need of medication or further exercise.
- Without side effects, serious and with good tolerance on the part of the participants.
Benefits for the heart and the thyroid
A subsequent study, published in 2024, he returned to parse this same intervention (intermittent fasting + low-carb diet), but this time focusing on how it affects the state of the myocardium and to the function of the thyroid.
After three months of intervention, the benefits observed were the following:
Cardiovascular health (state of the heart muscle)
- Reduction of the creatine kinase (CK): This enzyme is related to the muscle damage and energy metabolism. His descent suggests a protective effect on both the heart and on the muscles.
- Decrease of other enzymes myocardial:
- Lactate dehydrogenase (LDH)
- Creatine kinase MB (CK-MB)
- Hydroxybutyrate dehydrogenase (HBDH)
These enzymes are released when there is damage or stress or cardiac muscle. Their levels to drop indicates an improvement in cardiovascular health and muscle metabolism. That is to say, the benefits were not confined to lose weight or reduce glucose: also observed an improvement in the internal state of the body, especially in key organs such as the heart.
Thyroid function
- Reduction of TSH (thyroid stimulating hormone): When it is high, it usually indicates thyroid dysfunction. Its decline is a positive sign.
- Decreased T3 total and free (FT3): Reflects a reduction adaptive energy expenditure, which is common in conditions of fasting or restriction of carbohydrates.
- Increased free T4 (FT4): is Often interpreted as an improvement in the function of the thyroid gland.
- Reduction of the ratio T3/T4: Indicates a lower conversion of T4 to T3, an adaptation healthy in the context of weight loss and metabolic improvement. In other words, the thyroid gland responds intelligently to the new metabolic environment.
Fast Food and Evolutionary combined with other habits ancestral: reversal of the biological age
We know that we have two ages: chronological, that is the mark of our identity card, and the biological, which reflects the actual age of our cells. For example, a person 50-year time series could have 60 biological… or 40.
Well, it has been found that the intermittent fasting, when combined not only with a Power supply Evolutionary —rich in vegetables, fruits, antioxidants, polyphenols, probiotics, prebiotics, protein and quality fat, and low-carb— but also with physical exercise, breathing and relaxation techniques that can reduce stress, and adequate rest, you can reverse your biological age.
That is to say, not only slows the aging, but that can rejuvenate the body.
This conclusion comes from a study published in 2021, in collaboration with several universities in the usa. UU. and Canada. After applying these interventions during only eight weeks, the participants reduced their biological age in 3,23 years, as measured by the age of epigenetic DNA.
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We’ve come a long way since our ancestors ate when they could and what nature had to offer. Today, we have more options than ever, but also more confusion.
During my official training, I was taught —as it continues to teach even today— that:
• Carbohydrates should be the macronutrient main.
• Fats should be avoided; best all-skimming and “light”.
• Cereals are a staple food.
• Eat between 3 and 5 times a day.
Are recommendations that are still transmitted from official bodies, but what is certain is that, to this day, I have not found a single solid scientific evidence that supports these recommendations to improve health. Not one.
Return to simple patterns, consistent with the developments and our biology is not to look back with nostalgia: that is to move forward with intelligence.
It’s not about doing what is in fashion, but what makes sense.
This is not to blindly follow what “it has always been said”. It’s about choosing what works. Stop repeating mantras… and start listening to the science.
And to our own body.
