While protein from small game may be relatively easy to acquire, a diet lacking fat is unsustainable and leads to "rabbit starvation." In the wild, fat is the most critical and sought-after macronutrient for long-term energy, which is why predators often eat only the fatty parts of a kill, like the brain and skin.
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Calorie restriction alone is unsustainable because high-carb meals spike insulin, which sequesters energy from the blood into storage cells. The brain, which lacks storage capacity, perceives this drop in available energy as a crisis and triggers intense, overriding hunger, even if body fat is abundant.
Contrary to popular belief, fasting for up to four days actually increases your basal metabolic rate. Instead of shutting down to conserve energy, your body activates a hormonal 'fight-or-flight' response that increases energy expenditure to help you find food.
The "carbs vs. fat" diet war is a distraction. The body adapts to its fuel source, and on a caloric basis, excess energy from either carbohydrates or fats is stored as body fat to the same degree. Cutting calories from either source leads to similar weight loss.
While short-term keto adaptation (first month) may show no power gains, long-term adaptation (6-18 months) trains muscles to efficiently use fat as fuel. This results in significant power increases, with studies on soldiers showing up to a 50% improvement over their non-keto counterparts.
Feeling energetic isn't about consuming more calories. The limiting factor is how efficiently mitochondria transform and distribute energy to different systems. This reframes the problem of fatigue from insufficient energy production to inefficient energy allocation.
After becoming fat-adapted on a ketogenic diet, strategically inserting 1-2 days of high-protein, low-fat meals (e.g., lean protein and vegetables) can rapidly increase fat mobilization from your body's stores, leading to accelerated fat loss.
Unlike other mammals, human infants are born with significant fat stores. This fat provides essential nutrients like DHA and a source for ketones, which are the preferred fuel for the developing brain, especially in the first few weeks of life.
Unlike simple calorie restriction, intermittent fasting lowers insulin levels. This hormonal signal allows your body to access and burn its fat stores to make up for a caloric deficit, preventing the metabolic slowdown that typically sabotages diets.
The fitness trend of consuming very high amounts of protein (e.g., 1g per pound of body weight) is not supported by data. Amounts exceeding 1 gram per kilogram, especially from animal sources, can lead to systemic inflammation and promote the development of atherosclerosis (clogged arteries).
High protein intake can disrupt ketosis, but this is managed by slowing its absorption. Consuming protein with fat, fiber, and salt delays gastric emptying, preventing a rapid influx of amino acids and buffering the gluconeogenic response from the liver.