Health Claims

Your body absorbs omega-3s from fish oil better depending on the form they're in — free fatty acids are easiest to absorb, triglycerides are okay, and ethyl esters are the hardest.

Mechanistic

Walking every day — even if it's just regular walking, not exercise — is linked to living longer for older women.

Correlational

Walking about 7,500 steps a day helps older women live longer, but walking more than that doesn’t seem to add any extra benefit.

Quantitative

Older women who walk about 4,400 steps a day tend to live longer than those who walk only 2,700 steps. More walking is linked to lower risk of dying from any cause.

Correlational

Fish oil in triglyceride form gets absorbed better by your body than the kind in ethyl ester form.

Quantitative

If young, healthy guys eat protein before bed while lifting weights for 12 weeks, their muscle fibers grow way more than if they don’t — like almost double the growth, according to one study.

Causal

If young guys eat protein before bed while lifting weights for 12 weeks, they gain more leg muscle than those who don’t — about twice as much, according to one study.

Causal

If young, healthy guys lift weights for 12 weeks and drink a protein shake before bed, they get way stronger than those who don’t — like 30 more pounds on their lifts.

Causal

If young, healthy guys drink a protein shake with some carbs before bed while lifting weights for 12 weeks, they’ll probably gain more muscle and get stronger than if they just drank a fake shake with no calories.

Causal

Older guys who lift weights and take a protein shake after workouts and before bed get the same muscle-building effect as those who take a fake shake with the same calories — so the protein might not actually help at the molecular level.

Mechanistic

If older guys who are already active do full-body strength training three times a week for three months, they’ll get stronger legs and bigger leg muscles—even without adding extra protein to their diet.

Causal

For older guys who lift weights, having a protein shake with 3 grams of leucine right after workouts and before bed doesn’t help build more muscle or strength than just having a placebo drink with the same calories.

Causal

Older guys (60–75) who already eat enough protein don’t get stronger or build more muscle from extra protein shakes, even if they drink them after working out or before bed—just lifting weights is enough.

Causal

Older guys between 60 and 75 who aren't very active can get a lot stronger in just 12 weeks by lifting weights twice a week—even if they don’t take extra protein right after workouts or before bed, as long as they’re already eating enough protein overall.

Causal

For older guys in their 60s and 70s who already eat enough protein, taking 40 grams of protein right after working out or just before bed doesn’t help build bigger leg muscles any more than just working out — the muscle gains are about the same no matter when they take it.

Causal

Mixing plant and animal proteins—like soy with milk proteins—can work just as well for building muscle as using only animal proteins, especially after working out.

Quantitative

Eating more plant protein—like 60 grams of wheat protein in one meal—might help older adults build muscle just as well as smaller amounts of animal protein, like whey, even though plant proteins aren't as easily used by the body.

Mechanistic

Plant proteins might not help older people build or keep muscle as well as animal proteins because they're harder to digest and don't have as much of the important building blocks muscles need.

Mechanistic

If young adults who aren't used to working out eat a bit more protein—especially from whey or soy—and lift weights 3 times a week for 3 months, they’ll likely gain more muscle and get stronger, even if they weren’t eating enough protein to start with.

Causal

For young people new to lifting weights, taking soy protein or whey protein daily seems to have the same effect on thigh muscle growth.

Quantitative

If young adults who aren't used to working out do strength training 3 times a week for 12 weeks, they’ll gain about 1.5 kg of muscle and get stronger legs — and it doesn’t matter if their protein shake is made from soy or whey, as long as both have the same amount of leucine (2 grams per day).

Causal

If you're a young adult just starting strength training, drinking a shake with either whey or soy protein—both with the same amount of a key muscle-building amino acid (leucine)—will help you gain muscle equally well over 12 weeks.

Causal

Adding missing amino acids like lysine or methionine to plant proteins might make them better for building muscle, but we don’t have solid proof from human studies yet.

Descriptive

Mixing different plant proteins, like peas and rice, can give you all the amino acids your muscles need, just like animal protein.

Mechanistic