Slim and healthy into the summer with this eating strategy

In the 1980s, eating 5–6 meals per day became a common recommendation for people aiming to live healthily or lose weight. After more than 30 years it has become a nutritional dogma that’s hard to shake. The main rationale is that several small meals keep metabolism “revved,” supposedly making weight loss easier.

At first glance this sounds plausible, but fortunately this entrenched idea is losing ground. Evidence has been mounting in favor of the opposite, more natural approach. This style, with longer gaps between meals, is known as intermittent or periodic fasting.

Intermittent fasting isn’t a diet; it’s an eating pattern. You change not what you eat, but when you eat. That makes it one of the simplest nutrition-based ways to lose body fat while maintaining muscle mass.

Because it requires only a small behavior change compared with diets, it’s easier to sustain long term. It’s simple enough that nearly anyone can do it if their situation allows. Confining meals to a specific window effectively shifts body composition and boosts vitality.

Back to the Past = Progress

Instead of 5 to 6 meals daily, the older pattern of 3 meals without snacks is already a step in the right direction. That can also be viewed as a form of intermittent fasting.

The standout benefits of intermittent fasting appear with longer breaks than those between breakfast, lunch, and dinner. There are countless ways to apply it, and books and websites describe dozens of methods to make this biohack part of life.

Some skip breakfast, others dinner; some fast every other day and eat nothing for a full day. Less extreme versions include not eating every third day or once a week. Ultimately you choose the method that fits your situation and health.

In principle you eat a normal daily amount, but within a shorter timeframe than usual. An 8–9 hour window is common, but shorter blocks are possible.

– Diets are easy in the contemplation, difficult in the execution. Intermittent fasting is just the opposite — it’s difficult in the contemplation but easy in the execution. — Dr. Michael Eades.

Popular intermittent fasting protocols include: Leangains, Eat Stop Eat, The Warrior Diet, Fat Loss Forever, UpDayDownDay, Feast/Fast, 5:2 Diet, Renegade Diet, Carb Backloading, The 8 Hour Diet, Mini Fast Diet, The Fasting Diet, The 2 Day Diet, Eat Fast Slim, etc.

Intermittent Fasting and Evolution

Across roughly 250,000 years of human evolution, food wasn’t constant as it is now. It came in peaks and troughs.

Evolution favored building muscle and fat in times of plenty, then drawing on those stores in lean times. These natural—often seasonal—cycles kept bodies strong and healthy.

For the last ~100 years those cycles have largely disappeared; in the West we live in a perpetual “food peak.” To understand fasting, know the difference between the fed state and the fasted state.

The body is fed while digesting and absorbing—about 3–5 hours after a meal. In that hormonal state, fat burning is difficult.

After about 8–12 hours since the last meal, the body shifts to the fasted state. In this phase fat burning is easier because the hormonal profile differs.

Thus, fasting’s health and body-composition effects stem from our primal physiology. Because this pattern aligns with how our healthy, athletic ancestors ate, most people can benefit. Our “hardware” hasn’t changed much.

How Does It Work?

Fasting acts via multiple biochemical pathways and genes linked to health and improved body composition. It overlaps substantially with calorie restriction.

One mechanism is optimizing the clearance of dead and damaged cells—autophagy. The buildup of cellular “waste” from poor autophagy is seen by many experts as a key driver of aging and its risks.

Fasting also stimulates activity and growth of certain brain cells—evolutionarily sensible, since sharp cognition in scarcity improved survival: where was food found, and how to get it again?

Since 1946, animal studies have shown lifespan benefits. Today we know this pattern supports heart and brain health, cognition, mitochondrial efficiency, reduced oxidative stress, resilience, and better body composition.

Fasting Resets the Immune System and Sleep Cycle

The immune system benefits too. Research shows a 3-day fast with fewer than 200 calories per day can reset parts of immunity, clearing old immune cells and replacing them with new ones.

A 16-hour fast before breakfast can also help reset the body’s “sleep clock,” useful in a new time zone or after disrupted sleep.

Fasting, Ketosis, and Beta-Hydroxybutyrate

Beta-hydroxybutyrate (BHB) is a ketone produced in ketosis, a fat-burning state. BHB blocks genes involved in inflammation that are implicated in age-related diseases. You don’t need a strict ketogenic diet to benefit—intermittent fasting and exercise also raise BHB.

Longer periods without food naturally induce ketosis. Two days of fasting raise BHB about 12-fold; three days about 20-fold over baseline. Extended fasts aren’t required to benefit: after ~8 hours of fasting you’re essentially in ketosis and BHB begins to rise.

How Do I Apply It?

Fasting is a biohack worth trying. In a world where we’re never truly hungry, occasional hunger appears healthy. As noted earlier, brief stressors like hunger are hormetic.

Fasting isn’t for everyone. Do not fast if you’re under 18, pregnant, or breastfeeding. If you have medical conditions—especially diabetes or GI issues—consult your doctor first.

To see if it works for you, try it for a few weeks or months. One method may not fit, another might. Learn the basics first and stick to a single method at the start.

In short, intermittent fasting means pausing food for a set time, shrinking your eating to a defined window of hours. You don’t have to change what or how much you eat. During the fast, water, coffee, and tea are allowed; caloric drinks and supplements are not.