Peanuts aren't nuts. They're legumes, closer to lentils than almonds. What puts them with nuts is the fat: about half is the monounsaturated kind that makes olive oil cardioprotective. When it displaces the saturated fat in cheese or the carbs in a cracker, your LDL falls. The protein and fiber also slow how fast a meal hits your blood, so the glucose rise is gentler and the snack holds you longer than its calories should.

The lipid effect is directly measured: roughly two handfuls of nuts a day drops LDL about 7% ¹. The mortality finding is what makes peanuts unusual. In 120,000 people tracked thirty years, eating nuts most days was tied to a fifth lower chance of dying, and it held for peanuts alone ². A separate 200,000-person cohort of lower-income Americans and Chinese, where peanuts dominate nut intake, found the same 17–21% ³. The benefit plateaus at 28 g a day; twice that buys nothing more ⁴. People with type 2 diabetes get more: 27% lower cardiovascular death after adding nuts ⁵.

The target: 28 g a day, most days.

The first week is the satiety: the 11am snack holds you to lunch instead of leaving you raiding the kitchen. If your glucose runs high, the afternoon crash dulls, because peanuts flatten the rise after the next meal ⁶. Within a couple of months your lipid panel runs 5–10% lower on LDL, if the peanuts replaced something. The decade payoff is invisible day to day: the heart attack that didn't happen, the stent your sibling got and you didn't.

Tree nuts do the same thing. Walnuts carry a bit more plant omega-3, almonds more vitamin E, none of it decisive. The variable that is: cost. Walnuts and almonds run three to ten times more per gram, which is why the benefit showed up in lower-income households eating peanuts as their main nut ³. Rotate them in for variety; don't pay a premium believing almond butter does anything peanuts don't.