What intermittent fasting is, how it works in the body, its potential benefits, and the risks of applying it incorrectly.

Intermittent fasting has become one of the most popular nutritional strategies in recent years, especially among individuals looking to lose weight. While it can offer metabolic and health benefits, it is not without risks if practiced without proper knowledge or supervision.

Adriana Martín Peral – Neolife Nutrition Unit

What Is Intermittent Fasting?

Intermittent fasting is not a diet per se, but rather an eating pattern that alternates periods of food intake with periods of fasting. It focuses less on what you eat and more on when you eat. Unlike traditional diets, it is not based on restricting specific foods, but on structuring the timing of meals.

Main Types of Intermittent Fasting

16:8 Fasting

This involves fasting for 16 hours and concentrating food intake within an 8-hour window. It is the most popular protocol due to its ease of integration into daily life.

14:10 Fasting

A more flexible version, recommended for beginners or individuals with higher energy demands.

5:2 Method

Five days of normal eating and two non-consecutive days with significantly reduced caloric intake.

Alternate-Day Fasting

Alternates days of normal eating with days of complete or partial fasting. It is more demanding and less sustainable for many people.

How Does Intermittent Fasting Work in the Body?

During the first hours of fasting, the body uses stored glucose in the form of glycogen. Once these reserves are depleted, it begins to rely on body fat as a source of energy.

This process is accompanied by:

• A decrease in insulin levels
• An increase in glucagon
• Activation of cellular repair mechanisms

These changes explain many of the effects associated with intermittent fasting.

Positive Effects of Intermittent Fasting

When properly implemented and adapted to the individual, intermittent fasting may offer several benefits:

1. Improved Insulin Sensitivity

Lower insulin levels promote better blood glucose control, which may be beneficial for individuals with insulin resistance or risk of type 2 diabetes.

2. Fat Loss

By promoting fat utilization as fuel, it may contribute to weight loss, especially when combined with a balanced diet.

3. Metabolic Health

Some studies associate intermittent fasting with improvements in markers such as cholesterol, triglycerides, and blood pressure.

4. Possible Activation of Autophagy

Fasting activates cellular recycling processes known as autophagy, which are linked to cellular health and longevity, although their impact in humans is still under investigation.

Negative Effects if Done Incorrectly

Intermittent fasting is not suitable for everyone, and improper implementation may lead to adverse effects:

1. Nutritional Deficiencies

Reducing eating windows without proper planning may result in insufficient intake of protein, vitamins, and minerals.

2. Digestive Issues and Fatigue

Skipping meals without prior adaptation can cause dizziness, weakness, constipation, headaches, or gastrointestinal discomfort.

3. Unhealthy Relationship with Food

In some individuals, it may promote disordered eating behaviors, binge eating, or a rigid relationship with food.

4. Not Recommended in Certain Cases

It is not advisable for:

• Pregnancy and breastfeeding
• Individuals with eating disorders
• Individuals with eating disorders
• People with certain medical conditions without professional supervision

Common Mistakes When Practicing Intermittent Fasting

• Overeating during the eating window
• Prioritizing ultra-processed foods
• Not meeting protein requirements
• Forcing excessively long fasting periods
• Ignoring the body’s signals

Recommendations for Safe Intermittent Fasting

• Start gradually (14:10 before 16:8)
• Prioritize fresh, nutrient-dense foods
• Maintain proper hydration
• Adapt fasting to lifestyle and activity level
• Consult a nutrition professional

Conclusion

Intermittent fasting can be a useful tool within a healthy eating approach, but it is not a universal solution. Its success depends on the individual, the context, and proper nutritional planning. When practiced with knowledge and supervision, it may provide benefits; when applied incorrectly, it can lead to more harm than good.

BIBLIOGRAPHY

(1) Mattson, M. P., Longo, V. D., & Harvie, M. (2017). Impact of intermittent fasting on health and disease processes. Ageing Research Reviews, 39, 46–58.

(2) Anton, S. D., et al. (2018). Flipping the metabolic switch: understanding and applying the health benefits of fasting. Obesity, 26(2), 254–268.

(3) Patterson, R. E., & Sears, D. D. (2017). Metabolic effects of intermittent fasting. Annual Review of Nutrition, 37, 371–393.

(4) Organización Mundial de la Salud (OMS). Healthy diet factsheet.

La entrada Ayuno intermitente: qué es, beneficios y riesgos de una práctica cada vez más popular se publicó primero en Neolife.

Not everything is about the glycemic index, and you don’t need to “eat unlimited protein.”

If you want to lose body fat, you have probably heard that you should avoid foods with a high glycemic index and significantly increase your protein intake. But what truly matters? Does the glycemic index influence weight loss as much as we think? And how much protein do you actually need? Below, we clarify both concepts based on scientific evidence and practical application.

Adriana Martín Peral – Neolife Nutrition Unit

What Is the Glycemic Index?

The glycemic index (GI) measures how quickly a carbohydrate-containing food raises blood glucose levels compared with pure glucose.

• High GI → rapid rise in blood glucose
• Low GI → slower rise

However, there is a limitation: the glycemic index is measured under isolated conditions, with the food consumed alone and in standardized quantities. In real life, we eat combinations of foods. For this reason, a more practical concept is glycemic load, which takes into account both the quality and the quantity of carbohydrates.

Does the Glycemic Index Matter for Weight Loss?

Evidence shows that:

• Low-GI diets may improve glycemic control.
• They can be particularly beneficial in individuals with insulin resistance.
• However, when calories and protein intake are controlled, GI alone does not determine fat loss.

The factors that most strongly influence weight loss are:

• Sustained caloric deficit
• Adequate protein intake
• Long-term adherence

A high-GI food does not “cause weight gain” by itself. The overall dietary context is what truly makes the difference.

Protein: The Key Player in Fat Loss

If there is one macronutrient that becomes especially important when aiming to lose fat without losing muscle mass, it is protein. Why?

• It increases satiety.
• It reduces the loss of muscle mass during a caloric deficit.
• It has a higher thermic effect (the body expends more energy digesting it).

This leads to an important question:

How Much Protein Is Actually Needed for Weight Loss?

The standard recommendation for the general population is 0.8 g/kg/day.

However, for fat loss and preservation of muscle mass, current evidence suggests an intake of 1.6–2.2 g/kg of body weight per day. That said, before increasing protein intake, it is important to ensure that there is no medical condition requiring a different nutritional approach. Protein intake should always be individualized and supervised by a healthcare professional.

Practical example:

A person weighing 70 kg who wants to lose fat should consume between 112 and 154 g of protein per day. This does not mean “eating unlimited protein.” Beyond this range, the benefits do not increase significantly.

What You Should Really Focus On

Instead of becoming overly concerned with the glycemic index:

• Ensure sufficient protein intake at each meal.
• Combine carbohydrates with fiber, fats, and protein.
• Prioritize minimally processed foods.
• Evaluate your long-term adherence rather than focusing exclusively on GI.

Improving your daily protein distribution will have a much greater impact on body composition than focusing solely on the glycemic index.

Conclusion

The glycemic index can be a useful tool in certain contexts, particularly in individuals with metabolic disturbances, but it is not the decisive factor when it comes to fat loss. What truly makes a difference is maintaining a sustainable caloric deficit, ensuring adequate protein intake, and building a dietary pattern that can be maintained over time.

Within this framework, protein plays a key role because it helps preserve muscle mass, improves satiety, and facilitates adherence to the nutritional plan. However, more is not always better, and recommendations should be adjusted according to each individual’s characteristics and health status.

Ultimately, losing weight does not depend on demonizing foods based on their glycemic index or consuming unlimited protein, but rather on applying strategy, scientific evidence, and long-term consistency.

BIBLIOGRAPHY

(1) Thomas, D., Erdman, K., & Burke, L. (2016). Position of the Academy of Nutrition and Dietetics: Nutrition and Athletic Performance.

(2) Morton, R. W., et al. (2018). Protein intake and muscle mass: A meta-analysis.

(3) Wycherley, T. P., et al. (2012). Effects of energy-restricted high-protein diets on body composition.

(4) Livesey, G., et al. (2008). Glycemic index and body weight: systematic review and meta-analysis.

La entrada Glycemic Index and Protein: What Really Matters If You Want to Lose Weight se publicó primero en Neolife.

The menopausal transition promotes changes in body composition. We analyze the hormonal factors involved and the most effective nutritional strategies.

During menopause, many women experience weight gain, particularly in the abdominal area. Although this is often attributed exclusively to “hormones,” the phenomenon is more complex. The decline in estrogen levels, changes in muscle mass, and metabolic adaptations all play a significant role. We review what actually happens and how to intervene effectively.

Adriana Martín Peral – Neolife Nutrition Unit

Hormonal Changes in Menopause: What Really Happens?

Menopause is characterized by a progressive decline in estrogen levels, particularly estradiol. This hormonal shift impacts:

• Redistribution of body fat toward a more android (abdominal) pattern.
• Decreased basal energy expenditure.
• Increased insulin resistance.
• Higher cardiometabolic risk.

Estrogens play a protective role at the metabolic level. Their decline favors greater accumulation of visceral fat, which is metabolically active and associated with inflammation.

Is It Only a Hormonal Issue?

Not exclusively. In addition to hormonal changes, other factors are involved:

• Loss of Muscle Mass (Sarcopenia)

From the ages of 40–50 onward, there is a progressive decline in muscle mass if no strength stimulus is present. Since muscle is metabolically active tissue, its reduction decreases daily energy expenditure.

• Decreased Total Energy Expenditure

Lower levels of spontaneous physical activity, changes in sleep patterns, and increased stress contribute to a sustained positive energy balance.

• Changes in Appetite and Satiety

Some women report increased cravings for energy-dense foods, possibly related to hormonal fluctuations and sleep disturbances.

Evidence-Based Nutritional Strategies

• Prioritize Adequate Protein Intake: A sufficient protein intake (approximately 1.2–1.6 g/kg/day depending on individual profile) helps to:
  • Preserve muscle mass.
  • Improve satiety.
  • Support glycemic control.

Distributing protein evenly throughout the day optimizes muscle protein synthesis.

• Strength Training + Nutrition: Resistance training is key to counteracting age- and menopause-related muscle loss. When combined with adequate protein intake, it improves body composition beyond what is reflected on the scale.
• Control Energy Density: Reduce ultra-processed foods and prioritize:
  • Vegetables
  • Whole fruit
  • Legumes
  • Healthy fats (extra virgin olive oil, nuts)
  • Lean protein sources

This approach supports satiety while lowering overall caloric load.

• Fiber and Metabolic Health: A high fiber intake (25–35 g/day) improves:
  • Insulin sensitivity
  • Lipid profile
  • Gut health

The gut microbiota also appears to play a relevant role in weight regulation during this stage.

Sleep and Stress

Sleep deprivation is associated with greater insulin resistance and increased appetite. Therefore, intervention should be comprehensive and lifestyle-oriented.

What Does NOT Work

• Extremely restrictive diets maintained over time.
• Complete elimination of food groups without clinical indication.
• Focusing exclusively on weight without assessing body composition.

During menopause, the goal should be to improve body composition and metabolic health—not simply reduce body weight.

Conclusion

Weight gain during menopause is not inevitable, but it does require a different approach. The combination of appropriate nutrition, strength training, and a comprehensive lifestyle strategy can improve body composition and reduce cardiometabolic risk during this stage of life.

BIBLIOGRAPHY

(1) Lovejoy JC et al. Increased visceral fat and decreased energy expenditure during menopause.

(2) Lizcano F, Guzmán G. Estrogen deficiency and the origin of obesity during menopause.

(3) Stuenkel CA et al. Treatment of symptoms of menopause.

(4) Messier V et al. Menopause and sarcopenia: impact on metabolic health.

La entrada Menopause and Weight Gain: The Real Role of Hormones and How to Address It Through Nutrition se publicó primero en Neolife.

Ultra-processed foods are not designed merely to nourish us: they are carefully engineered to make us want to keep eating. It is no coincidence that opening a bag of potato chips or a packet of cookies almost always ends with “just a little more,” until, before we realize it, the package is empty.

These products (snacks, sweets, fast food…) may seem harmless, but behind their intense flavor, perfect texture, and irresistible aroma lie hours of testing, formulas, and fine-tuning aimed at stimulating our senses and activating the brain’s reward system. What exactly do these foods contain that makes them so hard to stop eating? Why can a single bite turn into a chain of cravings? The answer lies in their design: a precise combination of ingredients, textures, and sensory stimuli that subtly encourages us to keep eating.

Adriana Martín Peral – Neolife Nutrition Unit

What Are Ultra-Processed Foods?

Ultra-processed foods are products that undergo multiple industrial transformations and contain a long list of ingredients you would not normally find in a home kitchen. Beyond basic components such as wheat, corn, or milk, they often include added sugars, low-quality fats, flavor enhancers, additives, and texturizers, all designed to improve taste, appearance, and shelf life. The goal of these processes is not only to extend the product’s durability but also to create a perfect texture, an intense flavor, and a pleasurable eating experience, all while keeping production costs low. This is why, although they may appear to be simple snacks or ready-to-eat meals, each bite involves food engineering designed to capture our attention and keep us eating for longer.

How Ultra-Processed Foods Create Cravings

It is no coincidence that it is so difficult to stop after opening a bag of chips or a packet of cookies. Ultra-processed foods are designed to activate the brain’s reward system, releasing dopamine and making each bite more appealing than the last. This is achieved through what experts call the “irresistible triad”: sugar, fat, and salt. The precise combination of these three elements is carefully calibrated to maximize pleasure without becoming overwhelming, stimulating the release of dopamine, the neurotransmitter associated with pleasure and motivation.

Added to this is the concept of the “bliss point,” which describes the exact level of sugar, fat, or salt that produces the greatest satisfaction. Companies conduct extensive sensory testing to find the perfect proportion, ensuring that each bite is highly pleasurable and difficult to abandon.

Moreover, the texture and aroma of these foods are engineered to reinforce pleasure. The perfect crunch of potato chips, the melt-in-your-mouth smoothness of chocolate, or the softness of certain industrial breads send signals of freshness and flavor to the brain, increasing the compulsion to eat more. Even the low satiety of many ultra-processed foods (due to their low fiber or protein content) contributes to the brain continuing to ask for “just a little more,” even when the stomach is already full.

Ultra-processed foods do not rely solely on sugar, fat, and salt. Aromas and flavor enhancers also play a role in making each bite more irresistible. Ingredients such as monosodium glutamate (MSG), artificial flavorings, and industrial aromas intensify taste so that the brain perceives the food as more flavorful than it truly is. These additives provide no nutritional value but deceive our senses, generating a sense of pleasure that encourages continued consumption. It is a small chemical and sensory trick that, combined with other factors, makes stopping extremely difficult.

Another key factor is that many ultra-processed foods generate low satiety, meaning we do not feel sufficiently full despite having consumed many calories. This is because they tend to be calorie-dense but poor in fiber and protein—nutrients that help regulate appetite. As a result, the brain continues to send signals of hunger or craving even after sufficient energy intake. This combination of low satiety and high sensory reward turns these foods into an almost automatic cycle of eating more, again and again.

Marketing and Environment: Induced Cravings

It is not only ingredients and sensory engineering that make ultra-processed foods hard to resist; marketing and environment also play a key role in generating cravings and impulsive purchases. Bright packaging colors, eye-catching designs, and noisy wrappers are carefully designed to capture attention and associate the product with fun or pleasure.

In addition, many of these products are sold in small portions that seem harmless, leading us to underestimate how much we are consuming. This psychological design makes opening a package far more tempting and easy to eat “without guilt,” even though you may end up consuming more than planned.

Targeted advertising further reinforces these habits—not only in children, but also in adults. Commercials, social media, and promotions associate these foods with happy moments, rewards, or indulgence, creating emotional connections that go beyond simple hunger.

Finally, strategic placement in stores and supermarkets increases impulsive consumption. Positioning snacks at eye level, near checkout counters, or in main aisles makes them almost impossible to ignore. Even if you go shopping for a single ingredient to cook, constant exposure to these products activates the desire to buy and consume them immediately.

Together, these marketing and environmental factors do not merely sell the product—they manipulate our cravings, reinforcing the habits that ultra-processed foods have already begun to create through taste and texture.

Practical Example: Why Potato Chips Crunch the Way They Do

The crunch of potato chips does not happen by chance; it is the result of careful sensory engineering. Brands specifically adjust sound and texture so that each bite is highly pleasurable and encourages continued eating.

1. The crunching sound stimulates the brain

The characteristic “crack” activates brain areas associated with pleasure and the perception of freshness. Noisy foods are perceived as fresher, newer, and more desirable, and companies calibrate the hardness and shape of the chips to make the sound as “perfect” as possible. Studies have shown that when the crunch is amplified, people rate chips as tastier, even if they are exactly the same product.

2. Extremely low moisture content

Potato chips are fried until they contain only about 1–2% moisture. This extreme dryness makes their structure fragile, breaking into small fractures when bitten and producing a highly satisfying crunch. With more moisture, they would become chewy or soggy and lose this effect.

3. Porous structure and trapped air

During frying, the water inside the potato rapidly turns into steam, creating small internal bubbles. This microcavity-filled structure causes the chip to break into many particles at once when bitten, producing a more complex and pleasant crunch.

4. Fat and salt coating: the winning combination

The fat coating lubricates the mouth and enhances flavor, while salt intensifies taste and increases salivation. Together, fat and salt make the crunch more pronounced and the eating experience even more rewarding.

5. Crunch equals instant reward

The crunch reaches the ears milliseconds before the mouth perceives it, and the brain interprets it as “delicious.” This signal triggers a small dopamine release, reinforcing the habit of continuing to eat. That is why, even when we are full, sound and texture can push us to eat more than we need.

Conclusion

Ultra-processed foods are not simply foods: they are carefully designed products created to generate cravings. Their combination of flavor, texture, aroma, marketing, and low satiety activates brain reward circuits, creates automatic habits, and makes it difficult to stop—even when the body has already received enough energy. Understanding how these mechanisms work allows us to make more conscious choices and prioritize real foods most of the time, reducing the influence of strategies designed to keep us eating more.

BIBLIOGRAPHY

(1) Monteiro, C. A., Cannon, G., Lawrence, M., et al. (2019). Ultra-processed foods, diet quality, and health using the NOVA classification system. *FAO and Pan American Health Organizat

(2) SINC. Vinculan el consumo de ultraprocesados con síntomas depresivos y cambios en circuitos cerebrales. Agencia SINC. Agencia Sinc

(3) Sánchez Perona, J. “Los alimentos ultraprocesados se diseñan para ser muy apetitosos y fáciles de consumir”. Delegaciones CSIC. delegacion.andalucia.csic.es

(4) National Geographic. Alimentos ultraprocesados y su relación con la salud mental. National Geographic España

(5) El País. ¿Por qué los alimentos procesados son tan adictivos? Esta es la razón científica. Diario El País

(6) National Geographic. ¿Qué es más adictivo, la comida ultraprocesada o el tabaco? National Geographic España

(7) Lavanguardia. Entrevista con Claire Wilcox: “Alimentos con alto contenido en azúcar y ultraprocesados afectan al cerebro …”. La Vanguardia

(8) Business Insider (español). Ultraprocesados tan adictivos como el tabaco, según un nuevo estudio científico. Business Insider España

(9) El Economista. Por qué el cerebro es “adicto” a la comida ultraprocesada (y qué funciones puede alterar). El Economista

(10) El Tiempo. Los alimentos ultraprocesados serían dañinos para el cerebro, según estudio.

La entrada Why You Can’t Eat Just One: The Science Behind Ultra-Processed Foods and Cravings se publicó primero en Neolife.

Small eating habits with real impact (without going crazy).

Nutritional biohacking is the practice of optimizing your body and mind with small, strategic changes. But you don’t need implants or exotic supplements. Sometimes, the basics done right are enough.

Adriana Martín – Neolife Nutrition Unit

Nutritional Biohacking

Feeling more energetic, sleeping better, thinking more clearly… all that without following a strict diet or spending a fortune on exotic supplements. Welcome to the world of nutritional biohacking, a way to optimize your body through smart micro-habits you can start applying today.

The goal isn’t to follow an impossible routine, but rather to understand the key principles that regulate how you feel, eat, and function—and act on them strategically. Here are some simple yet powerful changes, backed by science and by the experience of those already practicing them.

Here’s the minimum effective dose you can do to feel better without complicating your life:

1. Start Eating Later (and Stop Eating Earlier)

Intermittent fasting is not just a trend: studies show that restricting your eating window to 8–10 hours improves insulin sensitivity, reduces inflammation, and supports mental clarity. If you have breakfast at 10 a.m. and dinner before 7 p.m., you’re in the game without extreme effort.

The best part? You don’t need to count calories or follow a specific diet—just give your digestive system a real break.

2. Micro-Doses of Caffeine, Not Energy Bombs

Many of us rely heavily on coffee to kickstart the day, but the ideal approach is small doses spread out: one cup after waking (waiting 60–90 minutes), another at midday, and none after 3 p.m. This way, you avoid the highs and crashes that affect your mood and sleep.

And if you can swap one of those cups for green tea or yerba mate, you’ll get extra benefits such as L-theanine, which smooths caffeine’s effect and boosts focus.

3. Eat Smart Fats for Your Brain

Sixty percent of your brain is made of fat, and what you eat directly affects its performance. Avocado, nuts, eggs, salmon, olive oil, and chia seeds are key allies. Adding these healthy fats not only keeps you fuller for longer but also enhances focus, memory, and mood.

A handful of nuts a day can literally make a difference.

4. Foods That Calm the Mind (Yes, Including Chocolate)

Low levels of magnesium, tryptophan, and zinc have been linked to anxiety and fatigue. You can support your mental well-being with foods like dark chocolate (at least 85%), bananas, spinach, lentils, oats, and plain yogurt.

You don’t need expensive supplements—just make sure your plate has a variety of colors and natural textures. Your nervous system will thank you.

5. Morning Sun

Minimum effective dose: 5–10 minutes without sunglasses.

• It regulates your biological clock (circadian rhythm), improves mood, and supports sleep.
• If it’s winter or you’re indoors, consider a natural light lamp.

Conclusions

You don’t need to make huge sacrifices to start feeling better. Nutritional biohacking is about doing the minimum necessary—but doing it with intention. Small daily changes, applied consistently, can generate a big impact over time.

Start today with just one. Pick the one that resonates most with you. And remember: your body is listening to everything you eat.

BIBLIOGRAPHY

(1) Panda, S., et al. (2016). Time-restricted feeding improves metabolic health. Cell Metabolism.

(2) NIH – Intermittent Fasting in Humans

(3) Haskell, C. F., et al. (2008). The combined effects of L-theanine and caffeine on cognitive performance and mood. Nutritional Neuroscience.

(4) Smith, A. (2002). Effects of caffeine on human behavior. Food and Chemical Toxicology.

(5) Dyall, S. C. (2015). Long-chain omega-3 fatty acids and the brain: a review of studies in depression. CNS & Neurological Disorders.

(6) Harvard Health Publishing: “The truth about fats: the good, the bad, and the in-between”

(7) Barbagallo, M., et al. (2010). Magnesium and aging. Current Pharmaceutical Design.

(8) Sarris, J., et al. (2015). Nutritional medicine as mainstream in psychiatry. The Lancet Psychiatry.

(9) Nehlig, A. (2013). The neuroprotective effects of cocoa flavanols. British Journal of Clinical Pharmacology.

(10) Asprey, D. (2014). The Bulletproof Diet. (referencia popular, no científica, pero influyente en la cultura del biohacking).

(11) Rhonda Patrick, PhD – Bioquímica especializada en nutrición funcional y salud cerebral.

(12) ZOE Health App / Tim Spector – Estudios sobre microbioma y alimentación personalizada.

La entrada Nutritional Biohacking: The Minimum You Can Do to Feel Better se publicó primero en Neolife.