Thermogenic Fat Burners for Weight Loss (Feeling the Burn)

America is obsessed with eating and it shows. Globally, there are more than 1 billion overweight adults; 300 million of those adults are obese, according to the World Health Organization (WHO). WebMD defines obesity as having so much body fat that your health is at risk. Consumers with a body mass index (BMI), a statistical measure of weight scaled according to height, of 30 or higher are considered obese. Along with diet, a decrease in physical activity is also a contributing factor to obesity; more than half of U.S. adults do not get enough physical activity to provide health benefits and 24 percent are not active at all during their leisure time, according to the Centers for Disease Control and Prevention (CDC).

With that much fat lying around, it’s no wonder weight loss is on the forefront of everyone’s mind. Diet choices are endless, with Weight Watchers, Jenny Craig, Atkins, Mediterranean, the Cabbage Soup diet and many more.

Burning fat has become a popular approach to weight loss, especially in dietary supplement category. Many consumers are using thermogenic (fat burning) dietary supplements along with diet and exercise to increase weight loss. Thermogenic dietary supplements are used to stimulate the body’s burning of fat; they boost the metabolic rate in the adipose tissue, which generates heat, hence the name thermogenics. Adipose tissue’s primary role is to store energy in the form of fat, but it also cushions and insulates the body. Brown adipose tissue (BAT) and white adipose tissue (WAT) are the two types of adipose tissue. The primary purpose of BAT is to generate body heat; however, most adults don’t have much BAT.

Basic Ingredients

Diet-induced thermogenesis is a popular way to improve fat burning and weight loss. Protein has recently received a lot of attention with new research showing its satiating ability as well as its thermogenic fat burning characteristics. The Royal Veterinary and Agricultural University, Copenhagen, Denmark, conducted a study comparing the effects of pork-meat protein, soy protein and carbohydrates on a 24-hour energy expenditure with 12 young, healthy, overweight and mildly obese nonsmoking men in a randomized, single blind, three-way crossover study lasting four days.¹ The study concluded substituting 17 to 18 percent of the carbohydrate energy with pork meat or soy protein produced 3 percent higher 24-hour energy expenditure. The animal protein in the pork meat produced 2 percent higher 24-hour energy expenditure than the soy protein.

In a separate study out of Mexico, researchers found when soy protein diets were consumed with a 5 percent fat or 25 percent high-fat diet, less weight was gained than when a casein protein diet was consumed, partly because of an increase in the thermogenic fat burning capacity mediated by uncoupling protein 1 (UCP-1).² The study suggested the type of protein consumed and the presence of fat in the diet modulate lipid metabolism in adipose tissue and liver.

Another study looked for differences in thermogenesis and macronutrient oxidation between lean and obese women.³ Fifteen lean and 15 obese women were studied on two occasions, one week apart. In one visit, they consumed a protein-rich meal; in the other visit, a fat-rich meal. The two meals were isocaloric, of equal volume and given in random order. Thermogenesis was not significantly different between lean and obese subjects after eating the protein-rich or the fat-rich meal; however it was significantly higher, by almost three-fold, after consumption of the protein-rich meal in comparison with the fat-rich meal in both study groups.

A recent study at Maastricht University, Netherlands, showed greater larger thermogenesis and fat burning after consuming protein versus carbohydrate may be related to the glucagon response that is induced by protein, but not by carbohydrates; protein-induced thermogenesis and glucagon response are not influenced by a carbohydrate pre- or post load.⁴ The researchers also reported protein ingestion can fully prevent the plasma glucose increase associated with a carbohydrate when carbohydrates are ingested after proteins.

A study published in Metabolism tested the effect of L-carnitine, a naturally occurring amino acid, on fat oxidation, protein turnover, body composition and weight development in slightly overweight subjects.⁵ L-carnitine created a significant increase in 13C-fat oxidation without protein catabolism; protein synthesis and breakdown rates remained unchanged.

Another basic ingredient used to stimulate thermogenesis is water. A 2007 study from the Franz Volhard Clinical Research Center in Berlin repeated previous studies that showed drinking 500 ml of water induces thermogenesis in normal-weight men and women.⁶ Researchers used overweight or obese but otherwise healthy subjects and compared the effects of 500 ml of isoosmotic saline or 50 ml of water. The study showed only 500 ml of water increased energy expenditure by 24 percent over a course of 60 minutes after ingestion, whereas isoosmotic saline and 50 ml water had no effect.

A more commonly known thermogenic fat burner that can really spice things up is capsicum frutescens or chili pepper. A study in 2003 evaluated 10 Thai women and their glucose response after a glucose drink and their metabolic rate with and without 5 g of fresh chili pepper.⁷ Thirty minutes after ingesting fresh chili pepper, the plasma glucose was 20.6 percent lower than the plasma glucose after the glucose drink without chili pepper. The chili powder increased the metabolic rate above resting metabolic rate (RMR). There was also an immediate increase of 20 percent in the metabolic rate within a few minutes of taking the chili pepper.