If you want to be leaner, then an excellent strategy is to make your diet more protein rich. Instead of sandwiches for lunch a protein shake can do wonders for your fat percentage, according to various studies. One from the Harbin Institute of Technology in China suggests that a protein shake works even better if it is made partly or wholly from rice protein.
The Chinese recently published the results of an animal study in Lipids in Health and Disease, in which they compared the effects of three proteins on fat metabolism: good old casein [CAS], an alkaline extract of rice protein [RP-A] and an alfa-amylase extract of rice protein [RP-E]. From literature studies the researchers knew that soya proteins have a better slimming effect than animal proteins; now they wanted to see if rice protein compared with soya protein.
Rats were given standard feed for two weeks, in which the proteins consisted of CAS, RP-A or RP-E. One kilogram contained 230-350 g protein extract, and the extracts consisted for 80-87 percent of protein. The researchers made their rice protein extracts themselves by the way.
The rats were seven weeks old and still growing. The animals that got RP-A or RP-E gained weight less quickly [by 17 and 19 percent respectively] than the rats in the casein group. On top of that they had 12 and 15 percent less fat.
So rice protein – and especially RP-E – has a slimming effect. This is probably because rice protein activates lipase enzymes in the blood vessel walls and in the liver. These cut up the fats in the blood, enabling the muscles and organs to absorb the free fatty acids and burn them.
At the same time, the rice proteins inhibited the FAS enzyme. Fat cells use this enzyme to store energy in the form of fat. The slower FAS works, the more opportunity the body has to burn fatty acids and glucose.
The rats in the rice protein groups became healthier: their blood concentrations of bad cholesterol and triglycerides decreased.
"Rice protein possesses a vital function in the modification of triglyceride metabolism, leading to an improvement of body weight and adiposity", the researchers conclude. "The precise mechanisms involved in the anti-adiposity responses to rice protein await more detailed investigation in further study."
Lipids Health Dis. 2012 Feb 13;11:24.