But those familiar with nutritional biochemistry know the fat issue isn’t that simple. Dietary fats vary in their activity in the body, leading to the present concept of so-called good and bad fats. Some forms of fat, such as linoleic acid
and alpha-linoleic acid
, can’t be synthesized in the human body and are therefore labeled “essential fatty acids
.” They’re further designated by their chemical structures, as in omega-6 and omega-3 fats.Even those fats, contrary to what many believe, aren’t totally “good” or “bad.” For example, they’re unsaturated and subject to oxidation with exposure to oxygen. While the body has antioxidant safeguards to prevent oxidation, they aren’t 100 percent efficient. Oxidation of unsaturated fats releases by-products called free radicals, which are unpaired electrons that seek to pair with other electrons. That wreaks havoc on essential systems. If free radicals attack the fats in cellular membranes, the internal cellular structure could be compromised, leading to mutations and cancer.
The type of dietary fat
most people associate with health problems is saturated fat. It’s usually solid at room temperature because its molecular structure has no openings in the hydrogen bonds. That has good and bad consequences. Since there aren’t any openings in the saturated-fat structure, it isn’t subject to oxidation. Saturated fat is also more chemically stable than are unsaturated and polyunsaturated (many openings) fats.The problem with saturated fat is that it acts as a substrate, or starting substance, for cholesterol synthesis in the liver. In fact, it’s more of an impetus to cholesterol production than is cholesterol itself, since the latter can only be partially absorbed in the diet, and the more you eat, the less the liver makes. But even saturated fat isn’t all that bad. It helps you absorb fat-soluble vitamins such as A, E, D and K. It also helps maintain the body’s testosterone levels. Studies show that you must take in a minimum of 20 percent of total calories as fat to maintain normal testosterone synthesis, and saturated fat is the preferred form of fat for that purpose.
Unsaturated and polyunsaturated fats are considered the primary “good” fats, since they usually lower cholesterol and are required to produce special hormonelike chemicals called eicosanoids, which are pivotal in myriad body functions. Eicosanoids are subdivided into such chemicals as prostaglandins, leukotrienes and others. The main categories of essential fats are omega-6
, consisting of various vegetable oils, and omega-3
, represented by flax
,fish oils 
and other foods.The problem with omega-6
and omega-3 fats is that their polyunsaturated structure makes them prone to rapid oxidation. To circumvent that, food scientists sought a way to make fats in food more stable. They modified the natural “cis” structure of unsaturated fats into a “trans” structure by adding hydrogen to fill in the openings on the polyunsaturated structure. That transformed a natural polyunsaturated fat into a bizarre fat with properties of saturated fat—like increased stability and resistance to oxidation.Unfortunately, trans fats, as they’re called, share none of the beneficial effects of saturated fat. Also unfortunately, they are ubiquitous in processed foods. Although they do exist naturally in small amounts in foods, the body has no use for them. Trans fats interfere with the metabolism of essential fats, including the production of vital eicosanoids.
Research shows that trans fats raise serum cholesterol levels even more potently than saturated fat. They also elevate production of low-density lipoprotein (LDL), a primary blood cholesterol transporter, while decreasing the number of LDL cell receptors. That increases the level of LDL circulating in the blood, making it more prone to oxidation. When LDL does oxidize in the body, what happens culminates in atherosclerosis and cardiovascular disease. Trans fats also increase the aggregation of platelets, or blood clotting, on the inside walls of arteries, thus increasing the arterial obstruction that causes heart attacks.
When trans fats invade cellular structures called mitochondria, further havoc ensues. The mitochondria are cigar-shaped structures in which energy as ATP is synthesized. They’re also the site of beta oxidation, better known as fat burning. Trans fatty acids displace the natural polyunsaturated fat structures in mitochondria, resulting in lowered oxygen intake, which leads to lower energy production and fat oxidation. In short, trans-fat intake promotes bodyfat increases.
A new study describes yet another insidious effect of trans fats: muscle loss.1 Focusing on the effects of trans-fat ingestion in 17 women and 15 men, age 38 to 83, the study found it interferes with the metabolism of essential fatty acids by inhibiting their conversion into eicosanoids. It turns out that some of these vital eicosanoids control protein metabolism and synthesis in the body, and when the trans fats lowered eicosanoid production, protein synthesis declined, leading to amino acid loss and subsequent muscle-tissue loss.
The authors suggest that, because of the universal availability of trans fats, it’s important to eat more essential fats, mainly omega-6, which are the primary precursors of active eicosanoids. Too much omega-6
, though, can lead to production of inflammatory eicosanoids, which are associated with joint pain and muscle soreness. Omega-6 sources of fat are also highly subject to oxidation, necessitating an increase in intake of stabilizing dietary antioxidants, such as vitamin E and selenium. Omega-3 fats
, by acting as a substrate for neutral eicosanoids, also modify and mitigate the bad effects linked to a high intake of omega-6 fats.The most prudent thing to do is to avoid trans fats, which are just garbage. Described on food labels as partially hydrogenated oils, they’re found in most processed foods, particularly cookies, baked goods, fast foods and processed frozen foods. Avoid this crap at all costs. Trans fats are bad for your health and your bodybuilding progress—unless getting fat and losing muscle are your definition of progress.
1 Hubbard, R., et al. (2003). Apparent skeletal muscle loss related to dietary trans fatty acids in a mixed group of omnivores and vegetarians. Nutrition Research. 23:651-658.
©,2013 Jerry Brainum. Any reprinting in any type of media, including electronic and foreign is expressly prohibited.
