🔥 Why Eating More Might Be the Best Thing You Can Do for Your Metabolism
🧬 What Is Energy Availability (EA) and Why Does It Matter?
If you’ve been cutting calories, skipping meals, or living off caffeine and willpower—but still feel tired, cold, bloated, or stuck—it’s not just you. And it’s not your fault. For decades, women have been told to eat less, move more, and avoid sugar at all costs. But modern science (and old-school common sense) tells a different story: your body needs fuel—real, consistent fuel—to thrive.
That’s where Energy Availability (EA) comes in. It’s a scientific way to describe how much energy your body has left over after exercise to run all the things that actually keep you alive: thyroid hormone production, detoxification, digestion, menstrual cycles, sleep, brain function, and immunity. When EA is too low, your body doesn’t have enough left to run those systems, so it starts downshifting—hard.
Most modern Americans—especially women—aren’t even close to meeting minimum EA. Compared to our ancestors and even our 1950s-era grandparents, we eat fewer calories, far less carbohydrate, and often fear sugar while overconsuming fat. This cultural shift, combined with chronic stress and government-endorsed low-calorie guidelines, has contributed to widespread metabolic suppression, thyroid dysfunction, fatigue, digestive issues, food sensitivities, and even chronic disease. Low Energy Availability is often the root cause—hidden beneath the surface of good intentions and “clean eating.” If you’ve ever felt like you’re “doing everything right” but still experiencing fatigue, sleep disturbances, or hormonal chaos, there’s a high chance you’re not hitting your EA.
🔬 Defining Energy Availability
Energy Availability is the amount of dietary energy left over for your body to run all its internal systems after you’ve accounted for exercise. In other words, it’s what’s left to support your thyroid, fertility, digestion, brain function, and immune system after movement is subtracted.
Scientifically, it’s defined as: EA = (Energy Intake - Exercise Energy Expenditure) / Lean Body Mass (kg)
Research suggests that a minimum of 45 kcal per kilogram of lean body mass (LBM) is required to maintain full physiological function in females. Anything under 30 kcal/kg LBM is considered Low Energy Availability (LEA), a state that induces metabolic suppression and hormonal dysfunction. (Loucks et al., 1998)
This is especially relevant for women who have dieted chronically, come from keto or intermittent fasting backgrounds, or engage in high levels of exercise.
🍽️ How We Got Here: Modern Eating vs. Ancestral Fueling
Modern Americans are eating far less energy—and far less carbohydrate—than our ancestors or even our grandparents. Post-WWII nutrition advice began to shift public perception toward fear of sugar and cholesterol, promoting high-fat, low-carb eating patterns and chronic caloric restriction.
Government dietary guidelines—like the 1,200–1,600 calorie "weight loss plans" pushed on women—have normalized under-eating. These intake levels, combined with stress, blue light exposure, and stimulant overuse (coffee for breakfast, anyone?), mean most people are running on fumes.
Compare that to the 1930s–1950s, when women often ate 2,400–2,800 calories daily, relied on carbohydrates like milk, fruit, potatoes, and sourdough, and had far less metabolic disease.
🧠What Happens When EA Is Too Low?
When you don’t eat enough to meet your energy needs, the body compensates. Hormones drop. Cortisol rises. Non-essential systems—like reproduction and digestion—get dialed down to conserve resources.
Common symptoms of LEA include:
Insomnia, especially waking at 2–4 a.m.
Low libido, infertility, or missing periods
Cold hands and feet
Anxiety or depression
Constipation and bloating
Weight loss resistance despite low intake
Weak immunity and poor wound healing
From a functional medicine perspective, low EA often underpins issues like hypothyroidism, estrogen dominance, and adrenal fatigue. You can’t out-supplement an energy deficit.
🧮 How to Calculate Your EA (and Fix It)
Estimate your Lean Body Mass (LBM): This can be measured using InBody scans, DEXA, or estimated based on body fat %.
Multiply LBM (in kg) by 45: This is your minimum intake goal in kcal/day.
Example: A woman with 50 kg LBM needs at least 2,250 kcal/day.
Add back food slowly if you’ve been under-eating: Reverse dieting is a strategic way to avoid weight gain while restoring EA.
Minimize cardio: Excess cardio drains available energy and prolongs LEA. Focus on strength training and low-intensity walking or Zone 2 movement.
Track consistently: Use tools like Cronometer to ensure you're hitting total calories. Prioritize meeting energy first, then macros.
đź“š Scientific References
Loucks, A. B., et al. (1998). Energy availability, not body fatness, regulates reproductive function in women. Exercise and Sport Sciences Reviews.
Mountjoy, M., et al. (2014). Relative Energy Deficiency in Sport (RED-S) Consensus Statement. British Journal of Sports Medicine.
Melin, A., et al. (2015). Energy availability and the female athlete triad in active women. Clinical Journal of Sport Medicine.
âś… Final Thoughts: EA Is the Foundation
You can’t rebuild your metabolism, restore your hormones, or heal your gut if you’re operating from a place of scarcity.
Energy Availability is the bare minimum—not a luxury. And while the mainstream may still push "eat less, move more," the science is clear: under-eating doesn’t just slow weight loss, it shuts down vitality.
Start by fueling generously, tracking accurately, and honoring your body's demand for nourishment. Reaching your EA is the difference between surviving and thriving. đź’Ş
