Seeing as how the MSBS students are starting to discuss metabolism, I thought this topic would be relevant. Below is a review of the study, “Energy expenditure and body composition changes after an isocaloric ketogenic diet in overweight and obese men.”
Obesity is described as the accumulation of excess body fat. Thought to be involved in this process are an increased proportion of dietary carbohydrates and high insulin secretion, aptly dubbed the carbohydrate-insulin model. Included within is the idea of a cellular internal starvation state, brought about via the decreased availability of fatty acids for metabolically active tissues, leading towards a decrease in energy expenditure and increased food intake.
Reasonable consequences of this model would be: an increase in fatty acid mobilization and oxidation, a decrease in hunger, increased body fat loss, and increased energy expenditure via the amelioration of the cellular internal starvation state due to a decrease in the proportion of dietary carbohydrates to fat, without altering protein or calories. A more conventional model, however, states that when calories are equated, there will be no substantial influence on energy expenditure or body fat loss.
The purpose of this study was to test the competing models by taking 17 obese men and confining them, voluntarily, to metabolic wards wherein they were expected to eat the entirety of meals provided with no access to outside food. While there, subjects consumed a high carbohydrate baseline diet for four weeks followed by a low carbohydrate ketogenic diet for another four weeks. This was done under supervision with dietary protein and calories kept consistent throughout.
Throughout the study, all subjects lost body weight and fat mass attributed to a negative energy balance. This led to the conclusion that an isocaloric ketogenic diet was not superior to a diet proportionately higher in carbohydrates in eliciting more fat or weight loss, as both the rates of body weight and fat loss were similar to baseline.
This study is important in the current context of nutrition and the laws surrounding specific licensure to practice nutrition and dietetics, as some states agree that it should be illegal for those lacking the necessary education and experience to perform individualized nutrition. For those without such legislature, an issue arises given the abundance of misinformation present on social media. I see this study as statistically significant evidence with which to assert over false claims that certain diets are superior to others. Overall, this increases the autonomy of the consumer by making them more knowledgeable and less susceptible to coercion, allowing them to be concerned more with dietary adherence when attempting weight loss, not which brands or products they have.
Hall, K. D., Chen, K. Y., Guo, J., Lam, Y. Y., Leibel, R. L., Mayer, L. E., Reitman, M. L., Rosenbaum, M., Smith, S. R., Walsh, B. T., & Ravussin, E. (2016). Energy expenditure and body composition changes after an isocaloric ketogenic diet in overweight and obese men. The American journal of clinical nutrition, 104(2), 324–333. https://doi.org/10.3945/ajcn.116.133561
Corey,
ReplyDeleteI appreciate that you chose this topic for your blog post. I am a college trade school instructor, and the bulk of my students are young women between the ages of 18 and 25. Almost daily there is talk about dieting and perceptions of body weight, beauty, and so on. The girls walk in with their venti iced coffee beverages (usually packed full of sugar), eat Flaming Hot Cheetos, and complain that they need to hit the gym and lose 20 pounds. It is honestly baffling to watch. I will typically utilize the chapters on nutrition to try to educate my students about what it means to have a balanced diet, and how weight loss really works. As you mentioned in your article, the patients involved in the study lost weight/body mass due to a negative energy balance, not due to any one diet in particular.
When we really take a look at the two most common diets, as mentioned in your post, we can clearly see the flaws. Low fat diets became popular in the early nineties when national guidelines challenged people to reduce fat to only 30% of their diets. In order to make up for the lost taste resulting from the reduction in fat, many brands took to upping the sugar and carbohydrate levels. Here, a comparison of nutritional content from Hidden Valley Ranch in regular and fat-free varieties:
Hidden Valley Original Ranch Hidden Valley Fat-Free Ranch
Serving size: 2 tablespoons 2 tablespoons
Calories: 140 kcals 30 kcals
Fat: 14 g 0 g
Saturated fat: 2.5 g 0 g
Protein: 1 g 0 g
Total carbs: 2 g (1 g sugar) 6 g (3 g sugar)
Sodium: 260 mg 310 mg
The regular ranch (left) has 14 grams of fat and 2 grams of carbohydrates. When we look at the “healthier” fat-free version (right), we do indeed see 0 grams of fat, but the carbohydrates are now more than double the original version at 6 grams. The fat-free version also contains more sodium, which is an issue given the cardiovascular diseases that are so common in this country.
This is just one example; pick almost any food product that has a “low-fat” version, and you will notice similar findings. The overarching issue here seems to be a lack of education on how to properly balance meals, and how to spot misleading “diets”.
References
Layarda, S. (2012, July 12). Nutrition Faceoff: Hidden Valley Original Ranch Dressing vs. Fat-Free. Health Castle. Retrieved October 3, 2021, from https://www.healthcastle.com/nutrition-faceoff-hidden-valley-original-ranch-dressing-vs-fat-free/