Fat is commonly known to be stubborn, unwelcomed, and misunderstood. We tend to demonize fat and blame it for the high rates of obesity and diabetes. Is fat a scapegoat? Or is it truly something we should fear? Sylvia Tara, the author of, The Secret Life of Fat, explained her frustrations with watching people around her eat whatever, and whenever, they want, while preserving their thin stature. This motivated her to learn the ins and outs of fat. While speaking to Tom Ashbrook from On Point, she explained, “Fat is not just fat.” Fat is an endocrine organ that produces hormones that are vital to our health. She encourages working with your fat, rather than against it. David Ludwig, a professor at Harvard Medical School states, “Body fat is so much more than a passive calorie storage depot,” (The Secret Life of Fat, 2017). Fat has the unique ability to use stem cells to “regenerate, increase our appetite,…and use bacteria, genetics, and viruses to expand itself,” (The Secret Life of Fat, 2017). Our body needs fat and we possess many defense mechanisms to protect and hold on to it.
Fat releases a hormone, known as leptin, which regulates appetite and metabolism. A major reason why people lose weight and quickly gain it back is because once fat is lost, leptin levels decrease, resulting in an increase in appetite and a decrease in metabolism.
Therefore, maintaining weight loss is often harder than the actual process of losing weight. After losing weight, it is important to reduce caloric intake by 22% in order to keep off the weight. For example, take someone who is naturally 150 pounds and compare their overall caloric intake to someone who originally was 170 pounds but who lost 20 pounds and is now 150 pounds. The person who is naturally 150 pounds can have an overall higher caloric intake than the person who lost 20 pounds and currently the same weight.
Not only is fat an energy reserve for our body, but also is crucial for brain, immune, and reproductive health. Sylvia Tara explains how brain volume is related to fat. Brain growth and development relies on adequate leptin levels. Furthermore, behaviors can often be different in those with lower levels of leptin. So what causes leptin levels to deplete? Either the loss of fat through behavior and lifestyle change, or from a genetic defect.
Fat is also important for immune health. Immune cells, known as T cells, have receptors for the hormone leptin, which help increase activity and propagation of these immune cells. If there is a low level of leptin, there are fewer T cells, causing you to become more prone to infection. As previously mentioned, the reason for low levels of leptin is either behavioral or genetic.
Reproductive health is also dependent on fat because fat produces estrogen. Oftentimes, when there is too little fat, there is a delay in puberty or even a loss in menstrual cycles, resulting in the inability to conceive.
Other factors besides diet and exercise that effect fat, are age and gender. Typically, men are more prone to have less fat than women. Also, as you age, you begin to lose hormones that are important for burning fat. For instance, a 65 year old woman would have different needs than a 25 year old man.
Research on fat remains controversial, however, there are certain views that are agreed upon. Most health professionals agree with the following:
1) Saturated fatty acids should be limited to 10% of total calories
2) Saturated fat should be substituted for polyunsaturated fats
3) Replacing fat with refined carbohydrates can equally be, if not more so, damaging to the body.
It is important to note that the research is ambiguous. As health professionals, we do not hold all the answers, and that can be scary. But as the field of nutrition grows, and the science and technology improves, we will have a better understanding on fat. With that being said, be cautious of fat, but do not be fearful of it. Focus on your overall dietary pattern, rather than specific nutrients in each individual food, and remind yourself that fat is important.
References
New Research Reveals Deep Truths About Fat. (2017). Retrieved August 11, 2017, from http://www.wbur.org/onpoint/2017/01/03/weight-loss-fat-science
The Secret Life of Fat by Sylvia Tara PhD. (2017). Retrieved August 11, 2017, from http://thesecretlifeoffat.com/
Zelman, K. (2011). The Great Fat Debate: A Closer Look at the Controversy– Questioning the Validity of Age-Old Dietary Guidance. Journal of the American Dietetic Association, 111(5), 655-658. Retrieved August 11, 2017, fromhttps://doi.org/10.1016/j.jada.2011.03.026.
Written by Nicole Lindel ~ Nutrition Education Master’s Student at Columbia University