Researchers in France conducted a study in 1992 that explored the connection between fat storage, thermogenesis, and the metabolic process. The study separated thirty-two women into three different experimental groups. The first were women of average weight without a history of obesity, the sec­ond were overweight women who had a history of obesity, and the third group was comprised of women who had just recently been experiencing weight gain and increased difficulty losing weight. The researchers gave each group a dose of pure glucose (sugar water) and measured how the women in each group metabolized the calories.

The results were astounding. The lean women in the first group processed the glucose with an increase in thermogene­sis. The overweight women in the second group did not expe­rience an increase in thermogenesis but rather stored the glucose. And the women in the third group, who were not obese but only recently experienced difficulty losing weight, also exhibited a failure in thermogenesis. The researchers con­cluded that a defect in thermogenesis may actually be a precur­sor to obesity.

Daniel B. Mowrey, Ph.D., author of Fat Management! The Thermogenic Factor, explains that “if the body loses its thermogenic capacity, obesity is certain to occur. It has been estimated that even a 0.1 percent deficit in the number of calories expended through thermogenesis could result in the accumulation of excess fat to the tune of 25 percent of body weight, i.e., obesity.”

Gamma linolenic acid (GLA), one of the most potent omega-6 fatty acids found in evening primrose oil, borage oil, and black currant oil, has been found to activate brown fat and boost the metabolic rates in healthy adults. GLA is the raw material needed for certain prostaglandins to ignite the mito­chondria’s fat-burning process in the body’s brown fat.

Interestingly, researchers in Heidelberg, Germany, have found that slimmer adults had a higher proportion of polyun­saturated fatty acids in their blood than did their heavier counterparts. Dr. David Horrobin, a highly respected essential fatty acid researcher, postulates that “fat people may be suffering from a polyunsaturated fatty acid deficiency.” Dr. Horrobin has found that GLA is remarkably effective in promoting weight loss, and that evening primrose oil is a particularly valuable dietary component in those who want to lose weight.

All too often, dieters on no-fat or low-fat plans will plateau after an initial weight loss. This can be a frustrating time for many dieters, especially when they don’t understand why they are not continuing to lose weight at the same pace they were initially. What has occurred is a downshift in the metabolic rate. After a certain period of time on a low-fat, low-calorie diet, the body will recognize the new, lower caloric intake as its sustenance level (it may even think it is starving!) and will slow its metabolism to match the new, lower caloric intake. Additional weight loss is stymied because your body now operates at a slower level, a level that may not be healthy but one at which you need fewer calories to subsist.

The only way to activate the metabolism again is to convince the body that it is no longer starving. Along with providing the body with balanced meals that contain adequate protein and  essential fatty acids.  Adding essential fatty acids to the diet is critical for boosting metabolic rate and activating the fat—burning engine.