Health Claims

After months of eating mostly fat and very little carbs, elite endurance athletes can burn fat much faster during long races, helping them save their body’s limited sugar stores for when they need a final burst of speed.

Quantitative

After a tough leg workout, drinking a sugary sports drink instead of water helps your muscles refill their energy stores faster, so you recover better after six hours.

Quantitative

Whether you're male or female, if you lift weights, you're likely to gain muscle and strength at about the same rate — even though guys usually start with more testosterone than girls.

Descriptive

If you're new to weight training, you can expect to build about 1.5 kg of muscle in the first couple of months, but after six months, your gains slow down a lot—and after that, you’ll probably only gain less than 2.5 kg of muscle per year if you’re not using steroids.

Quantitative

Working out until your muscles burn and swell up doesn't actually make them grow bigger over time—those sensations are just side effects, not the real reason muscles get bigger.

Mechanistic

Glycogen depletion during resistance training is negligible in non-fasted individuals performing ≤10 sets per muscle group per session.

Quantitative

Lifting weights makes your muscles bigger, and the main reason is how much total work you do—like how heavy the weights are, how many sets and reps you do, and how long you hold the tension. More total work = bigger muscles.

Mechanistic

Low-carbohydrate, high-fat diets are associated with higher basal testosterone levels compared to high-carbohydrate diets in healthy adults.

Assertion

Adequate dietary protein intake stimulates sufficient insulin secretion to maximize suppression of muscle protein breakdown, rendering additional carbohydrate intake redundant for insulin-mediated anabolic signaling.

Assertion

Glycogen re-synthesis can occur on a low-carbohydrate diet within 24 hours via gluconeogenesis from lactate, glycerol, and amino acids.

Assertion

High-intensity resistance exercise derives a substantial portion of its energy from the creatine phosphate system and aerobic fat oxidation, particularly during rest intervals.

Assertion

Resistance training is energetically inefficient in terms of total caloric expenditure due to predominant eccentric muscle actions and prolonged inter-set rest periods.

Assertion

Typical resistance training sessions deplete muscle glycogen by no more than 40%, even under high-volume conditions.

Quantitative

Muscle glycogen serves as the primary endogenous fuel source for high-intensity resistance exercise.

Assertion

Carbohydrate intake has no significant effect on muscle hypertrophy when protein and total energy intake are held constant.

Assertion

Feeling like you’ve eaten something before a workout — even if it’s just a fake meal with no calories — can make you lift more, not because of carbs, but because you feel less hungry or more ready.

Correlational

Whether you eat a lot of carbs or very few for months, your strength and muscle growth won’t change — as long as you’re eating enough total calories and protein.

Correlational

Eating a lot of carbs for a few days before a workout won’t make you stronger — even if you eat way more calories than usual. Your body can refill its energy stores just fine without extra carbs.

Correlational

Eating carbs after a super-hard workout helps you perform better — but only if you were starving before. If you ate the same number of calories from protein or fat, carbs don’t help any more.

Correlational

If you’re doing a ton of sets for one muscle group (like 12+ sets of squats) or training twice in one day, eating more carbs might help you push harder — otherwise, it doesn’t matter much.

Correlational

Eating carbs before a normal weight workout doesn’t make you stronger or let you do more reps, unless you’re training super hard with lots of sets or haven’t eaten all day.

Correlational

The two muscles on the side of your arm tend to turn on and off together, but your biceps often turns on when they turn off — like they’re taking turns instead of working as a team.

Descriptive

Your biceps works more efficiently when your forearm is turned palm-down — it doesn’t need to work as hard to twist your hand — but the muscle that turns your palm down doesn’t get more efficient when stretched.

Descriptive

How stiff your bicep feels when you bend your elbow depends on both how bent your elbow is and which way your palm is facing — but how hard your brain tells your bicep to work doesn’t change as much with that combination.

Correlational