Conjugated Linoleic Acid, or CLA, is a naturally occurring group of omega-6 fatty acids found primarily in the meat and dairy products of grass-fed ruminant animals. It is widely sold as a dietary supplement, typically synthesized from vegetable oils like safflower oil, and has gained popularity as a purported aid for managing body composition. The marketing often positions CLA as an agent for fat loss and muscle gain. This article investigates whether this supplement can paradoxically cause weight gain, contrasting this concern with its intended use as a weight management tool.
Understanding CLA and Its Intended Metabolic Role
The primary reason individuals turn to CLA supplementation is its theorized ability to positively alter the ratio of fat mass to lean muscle mass. Researchers believe CLA influences how the body stores and breaks down fat through several biological pathways. One key mechanism involves inhibiting fat storage within adipocytes, or fat cells, by reducing the activity of enzymes necessary for fat uptake, such as lipoprotein lipase. CLA is also thought to promote fat breakdown, a process known as lipolysis, which encourages the body to use stored fat for energy. Furthermore, the supplement is marketed to help preserve or even increase lean muscle mass, especially when combined with a regular exercise regimen. These intended effects on muscle preservation and fat reduction are the basis for CLA’s reputation as a body recomposition supplement.
Addressing the Weight Gain Question Directly
The concern that CLA might cause weight gain stems from the fact that scientific findings in humans are often inconsistent and show only modest effects on body composition. While the supplement is marketed for fat loss, many large-scale human trials have demonstrated that CLA does not significantly decrease total body weight or Body Mass Index (BMI). Some studies have shown a small reduction in body fat mass, but this reduction is frequently marginal, often averaging less than a pound or two over several months.
Unexpected weight increase while taking CLA can sometimes be a reflection of changes in body composition rather than a true negative effect. If a user is also engaging in resistance training, the preservation or increase of lean muscle mass can lead to a stable or even slightly higher number on the scale, since muscle tissue is denser than fat. However, the possibility of genuine fat gain cannot be dismissed entirely, as some individual results in studies have been highly variable, with a small number of participants unexpectedly gaining fat mass.
Other Reported Metabolic and Digestive Effects
Users should be aware of other reported side effects associated with CLA supplementation. The most commonly reported issues are gastrointestinal in nature, often attributed to the high concentration of fatty acids consumed in supplement form. These mild digestive disturbances include symptoms such as:
- Nausea
- Diarrhea
- Flatulence
- General stomach upset
More concerning are the potential negative impacts on metabolic health, particularly involving the trans-10, cis-12 isomer, which is a common component in supplements. Studies have linked CLA consumption to a decrease in insulin sensitivity in some individuals, which could negatively affect blood sugar regulation. There is also evidence suggesting that high doses of supplemental CLA may lead to a reduction in high-density lipoprotein (HDL) cholesterol and may contribute to fat accumulation in the liver.
Practical Dosage and Safety Guidelines
The daily dosage of CLA used in human clinical studies generally falls within the range of 3.2 grams to 6.4 grams. Research suggests that a daily intake of at least 3 grams is necessary to achieve any potential effect on reducing body fat. To minimize the risk of digestive discomfort, it is often suggested to take the supplement with meals.
While CLA is generally considered safe for healthy adults when taken within the recommended dosage range, certain individuals should exercise caution or avoid it entirely. Due to the potential for adverse effects on glucose metabolism, people with pre-existing metabolic syndrome or type 2 diabetes should be particularly careful. Individuals with known liver conditions, as well as those who are pregnant or nursing, should not take CLA. It is important to consult a healthcare provider before starting any new supplement regimen.