Black pepper may help you lose weight.  

Black pepper

Like many other spices, black pepper boasts fat-burning properties.  The active ingredient in black pepper is peperine.  It appears that adding a little a little pepper to your food will help with weight loss.  Before you run out and buy yourself a pepper grinder or hit the vitamin store to look for it in pill form, let’s take a look at the research.  

Research on black pepper and weight loss:

1. Black pepper appears to boost metabolism.  Black pepper is a thermogenic food that seems to have similar fat-burning effects as a 20-minute walk[1].  It has been suggested that black pepper affects lipid metabolism and increases metabolism.  The supplement used in this study did have concentrated capsaicin in it also.  Another study showed that black pepper increase carbohydrate and fat metabolism in the skeletal muscle of mice[2].  More research is needed.  
2. Black pepper appears to reduce insulin resistance.  One major study shows that black pepper reduces insulin resistance[3].  Insulin resistance is the primary cause of the metabolic syndrome.  If you have lower insulin resistance, your cells will require less insulin to clear your blook of excess glucose or blood sugar.  Excess insulin is a significant cause of central obesity, and even worse it results in an increase in appetite.  
3. Black pepper reduces fat cell creation.  Each fat cell has a limit on the amount of fat it can store.  If more storage is needed, adipogenesis creates new cells to expand storage. Research has shown that black pepper blocks the ability to make new fat cells and reduces adipogenesis[4].  

The bottom line: Black pepper appears to boost metabolism, reduce insulin resistance, and block an expansion of fat storage.  The studies are limited and were done on cells grown in a petri dish and mice.  I personally find that I eat less if I add a good amount of pepper to each dish.  More research is needed, but if you do not have black pepper as one of your staple species, try adding black pepper to just about everything you eat.  Then again, I did not find it tasted good with yogurt or ice cream.