Even though I am only 24, it seems as though my metabolism has slown way down, so I've been trying to eat the right foods to get it up again! Here are some to try:

Spicy Kale and Lemon Israeli Couscous
  For the capsaicin shy, there’s just a touch of heat in this recipe from the   crushed red pepper flakes.

Slow-Cooked Spicy Black Bean Soup
  A slow-cooked recipe for those who say they have no time.

Acorn Squash with Fenugreek Seeds
  As we said, properly hot, the heat derived from two dried whole red chile peppers.

Korean Spicy Stir-Fried Squid
  Gochujang is a fermented red chile pepper paste that spices up many Korean dishes.

Gai Yang with Bird’s-Eye Chile Dipping Sauce
  Bird’s eye chiles (Thai chile peppers) make the dipping sauce a hard-to-resist   blend of sweet and spicy.

Paul’s Venezuelan Chocolate Chile Chicken
  Fresh red chiles turn the sauce in this chicken dish fiery, reminiscent of mole.

Spicy Black Bean Tacos
  Pan-roasted jalapeños add a nice kick to this Tex-Mex classic.

Southwestern Meatballs
  As Beth Velatini warns, serrano peppers are dangerously hot.

Shrimp Pasta with Spicy Tomato Sauce
  A pleasant background heat from jalapeños permeates the sauce for this pasta;   for a healthier dish, try using whole-wheat pasta or pasta made from spelt or   quinoa.

Tilapia with Spicy Kumquat Salsa
  Fish seasoned with cayenne and a jalapeño-kumquat salsa on top makes this a   metabolism-boosting powerhouse.