BMR (Basal Metabolic Rate)
The calories your body burns at complete rest, just to keep you alive. Calculated via the Mifflin-St Jeor equation. Typically 1,200-1,800 cal/day for adults. Sets the floor for all macro math.
Nutrition & Macro Glossary
Every nutrition term you need — defined plain. Click any term to copy a direct link.
TDEE (Total Daily Energy Expenditure)
BMR plus all the calories you burn through movement, digestion, and exercise. This is your maintenance calorie target. Calculated as BMR × activity multiplier (1.2 sedentary → 1.9 athlete).
RMR (Resting Metabolic Rate)
Very similar to BMR but measured under less strict conditions. About 10% higher than BMR. Often used interchangeably in casual nutrition writing.
NEAT (Non-Exercise Activity Thermogenesis)
The calories you burn fidgeting, walking around the house, standing at your desk — all the movement that isn't formal exercise. NEAT varies more between people than any other component (can swing 1,000+ cal/day).
TEF (Thermic Effect of Food)
The calories your body uses to digest, absorb, and metabolize what you eat. Protein has the highest TEF (~25%), carbs ~8%, fat ~2%. Why high-protein diets feel "lighter."
Macros / Macronutrients
The three nutrients your body needs in large amounts: Protein (4 cal/g), Carbohydrates (4 cal/g), and Fat (9 cal/g). Alcohol is sometimes called a "fourth macro" at 7 cal/g.
Calorie Deficit
Eating fewer calories than you burn. Required for weight loss. Typical sustainable deficit: 300-500 cal/day. Larger deficits trigger metabolic adaptation faster.
Calorie Surplus
Eating more calories than you burn. Required for muscle gain. Typical "lean bulk" surplus: 200-300 cal/day. Larger surpluses add more fat than muscle.
Recomp (Body Recomposition)
Losing fat while gaining muscle simultaneously. Easiest for beginners, dieting returners, and the obese. Hardest for lean experienced lifters. Usually requires eating at maintenance with very high protein.
IIFYM (If It Fits Your Macros)
Flexible dieting approach: any food is allowed as long as it fits your daily macro targets. Origin: powerlifting community 2010s. Often misunderstood — best results pair flexibility with mostly whole foods.
Bulking
A deliberate calorie surplus to gain muscle, accepting some fat gain. "Clean bulk" = small surplus, mostly whole foods. "Dirty bulk" = aggressive surplus including junk food. Most lifters benefit from clean.
Cutting
A deliberate calorie deficit to lose fat, ideally preserving muscle. Higher protein + resistance training = better muscle retention. Typical cut duration: 8-16 weeks.
Maintenance
Eating at TDEE — your weight stays stable. Useful diet break between cuts and bulks. Critical for resetting hormonal markers after a long deficit.
Refeed
A planned 1-2 day increase in carbs (back to maintenance or above) during a calorie deficit. Restores leptin, glycogen, and training performance. Distinct from a "cheat day."
Diet Break
A planned 1-2 week period eating at maintenance during a long cut. Restores hormones, sanity, and adherence. Strongly evidence-backed for long fat-loss phases.
EAAs (Essential Amino Acids)
The 9 amino acids your body can't make — must come from food. Found complete in animal proteins; plant proteins need combining. Particularly important: leucine for muscle protein synthesis.
BCAAs (Branched-Chain Amino Acids)
Three of the 9 essential amino acids: leucine, isoleucine, valine. Marketed heavily as supplements but redundant if you hit your protein target through food/whey.
Complete Protein
A protein source containing all 9 essential amino acids in adequate amounts. All animal proteins are complete. Plant complete proteins: quinoa, soy (tofu/tempeh/edamame), buckwheat, hemp.
Glycogen
How your body stores carbs (in muscle and liver). 1g of glycogen holds ~3g of water — explains the rapid weight drop when starting low-carb (and rapid regain when carbs return).
Ketosis
Metabolic state where your body burns fat for fuel instead of carbs, producing ketones. Requires very low carb intake (under ~20-50g/day). Different from "fat-burning" — most fat loss happens without ketosis.
Net Carbs
Total carbs minus fiber (and sometimes sugar alcohols). Popular in keto/low-carb circles. Fiber doesn't spike blood sugar, so subtracting it gives a more useful number for blood glucose response.
Protein Synthesis
The process where your body builds new proteins (muscle, enzymes, hormones). Maximally stimulated by ~0.4g/kg leucine-rich protein per meal, every 3-5 hours.
Catabolic / Anabolic
Anabolic = building (muscle, tissue). Catabolic = breaking down (fat, but also muscle in extreme deficits). "Anabolic window" post-workout is overhyped — total daily protein matters most.
P-Ratio (Partitioning)
How your body splits surplus calories between muscle and fat (in a bulk), or deficit between fat and muscle (in a cut). Better p-ratio = more favorable composition change. Improved by lifting, sleep, and adequate protein.