Health Claims

After a hard weight workout, your body burns more total calories during your next cardio session than if you did light weights or no weights first.

Correlational

Whether you do heavy or light weights before cycling, your body still burns the same amount of carbs during the bike ride.

Correlational

After a tough weight session, women tend to breathe harder during their cardio workout than after an easy weight session or no weights, but men don’t show this difference as clearly.

Correlational

Doing a tough weight workout before jogging or cycling helps your body burn more fat while you're doing the cardio.

Correlational

Most studies measure muscle growth by weighing your whole body and subtracting fat — but that includes water and fuel, not just muscle. That’s like measuring your car’s weight to see if the engine got bigger.

Descriptive

Eating fewer carbs can make you feel fuller and eat less overall — which might make it harder to gain muscle because building muscle needs extra calories.

Quantitative

We can’t say for sure if carbs help build muscle — the data is too shaky. It might help a little, but we just don’t have strong enough proof yet.

Quantitative

When you eat more carbs, your muscles look bigger because they hold more water and fuel — not because the actual muscle fibers grew. Ultrasound can tell the difference; body composition scales can’t.

Quantitative

Eating more carbs doesn’t make your muscles grow bigger when you’re already getting enough protein and calories — your muscles respond more to lifting weights than to how many carbs you eat.

Quantitative

Mixing up heavy and light weights in a workout burns more muscle sugar than sticking to one weight the whole time—likely because you do more total work.

Quantitative

People who don’t lift weights regularly lose more muscle sugar during a workout than those who train regularly—likely because their bodies are less efficient at using energy.

Quantitative

Surprisingly, lifting heavier weights doesn’t burn more muscle sugar—it actually burns less, possibly because you can’t do as many reps.

Quantitative

The longer you lift weights in one session, the more your muscle sugar gets used up—every extra minute burns about 1.3 more units of energy.

Quantitative

The more sets you do in a weightlifting workout, the more your muscle sugar stores get used up—each extra set burns about 11 more units of energy.

Quantitative

After a weightlifting workout, the main leg muscle loses a lot of its stored sugar energy—about 21% on average—which can make you feel tired and affect how well you do in your next workout.

Quantitative

The ketone drink made half the guys feel sick to their stomach — bloating and nausea — but didn’t change their ketone or blood sugar levels, meaning the side effects aren’t linked to the good effects.

Descriptive

In lab-grown muscle cells, adding ketones along with leucine (a muscle-building amino acid) makes the 'grow' signal way stronger and actually increases how much protein the cells make — ketones aren’t just fuel, they help the signal work better.

Mechanistic

After a hard workout, ketone drink helps your muscles calm down their 'energy alarm' (AMPK) twice as fast as a placebo, likely because ketones give your muscles another fuel to burn and restore energy quicker.

Causal

Drinking ketone drink after a hard workout doesn’t help your muscles refill their energy stores any faster than drinking a fake drink — even if your blood ketones are high.

Causal

When trained guys drink a special ketone drink after a tough leg workout (and also eat protein and carbs), their muscles send stronger 'grow' signals than when they drink a fake version — even though their insulin levels are the same.

Causal

For athletes who need to make weight (like wrestlers or boxers), eating low-carb and high-fat for a long time might help them lose fat without losing muscle, which is safer than starving or sweating off weight quickly.

Descriptive

You can’t just switch to a low-carb, high-fat diet and expect to perform better in endurance sports right away—it takes months for your body to adjust and start burning fat efficiently.

Descriptive

Eating a high-fat, low-carb diet for a long time might make you feel more tired during long races because it increases certain chemicals in your blood that can affect your brain and make you feel sluggish.

Mechanistic

Even when eating almost no carbs after a race, athletes who’ve been on a high-fat, low-carb diet for months can still rebuild their muscle sugar stores just as well as those eating lots of carbs.

Quantitative