Paige Roberson | December 29th, 2024
Have you ever wondered why there are so many diets out there that claim to help people lose weight, but none of them work perfectly for everyone?
The answer lies in the fact that the effect of a diet is different for everyone based on their genetics, lifestyle, and microbiome. This complexity highlights the need for a more personalized approach to weight management.
Factor #1: Genetics
Each person has different genetics that can make a meal that is healthy for their friend unhealthy for them. This is because a person’s genetics are linked to their absorption of food, metabolism, enzyme digestion, storage, excretion, and many other factors that play into the nutritional impact of a meal. For example, some people can’t have dairy products in their diets due to the genetic inability to digest lactose.
Genetics can also determine what foods people like and dislike. For instance, TAS2R38 is a taste receptor gene that controls the ability to taste bitter compounds like phenylthiocarbamide (PTC), found in cabbage, kale, and other vegetables. “TAS2R” stands for Taste 2 Receptor, and 38 is the number of the gene. Genes such as TAS2R38 can alter a person’s diet completely because they are less likely to eat certain foods due to a dislike for the food’s taste.
Genetics can even affect obesity. For example, people with the gene PPARγ have increased sensitivity to insulin, more high-density lipoproteins, and increased glucose utilization. All of these act as protective mechanisms against obesity and diabetes, potentially lowering the degree to which people with this gene must regulate their diet to avoid obesity.
Factor #2: Lifestyle
Even if everyone had the same genetics, we would still have vastly different lifestyles. One study had 1,102 healthy people eat identical meals for two weeks and measured their glucose, insulin, and triglyceride fats (which are risk factors for obesity and other diseases). The participants’ sleep, exercise, and hunger levels were also tracked, and stool samples were collected to assay their gut microbes. The study found that there were significant differences in how people reacted to their diets despite eating the same things, and lifestyles played a major role in these differences. For example, people who slept for an adequate amount of time and did physical activity most days could be expected to lose weight more easily because they were burning more calories and not harming their hunger-regulating hormones, which translated to improved insulin sensitivity in the study.
Factor #3: Microbiome
The most important of these three aspects that separate the effectiveness of various diets on people is their microbiome. The microbiome is the community of bacteria and microorganisms that live in the gut and play a crucial role in how the body processes food. Everyone has a unique microbiome, which affects how they’re able to digest food, absorb nutrients, and metabolize. A diverse and balanced microbiome helps break down food efficiently, extract nutrients, and regulate fat storage, while a lack of beneficial bacteria can hinder these processes.
For instance, some gut bacteria are more efficient at converting certain foods, like fiber, into fatty acids that promote fat-burning and reduce inflammation. Additionally, the microbiome influences the body’s sensitivity to hormones like insulin, which impacts how we store or use energy from food. This is why a diet that works for one person might not have the same effect on another — their gut bacteria respond differently to the foods being consumed. The microbiome’s role in digestion and metabolism highlights the importance of a personalized approach to nutrition that takes into account not only what we eat but how our gut processes those foods.
By making small adjustments, such as choosing whole foods, prioritizing sleep, and staying active, you can support your body’s natural ability to metabolize food and maintain a healthy weight. With the resources and knowledge available on campus at Vanderbilt, including access to registered dietitians and nutritional counseling, Vanderbilt students can tailor their diets to their personal needs. After all, optimizing your diet isn’t just about weight management — it’s about feeling your best academically and socially, supporting your body’s performance, and fostering long-term health. By embracing a more individualized approach to eating, you can enhance both your academic and personal life, all while nourishing your overall health.
Although there is no perfect diet, there are certain foods that you can eat to obtain the most nutritional value. As you craft your diet, make sure to prioritize high-quality food — unrefined, minimally processed foods such as fruits, vegetables, whole grains, and healthy fats. Many of these foods are found in the healthy eating plate and are available in dining halls across Vanderbilt’s campus. So as you determine what you want to eat each day, ask yourself if that meal will contribute to your nutritious, microbiome-friendly diet.
References
The Best Diet: Quality Counts. Nov. 2013, https://nutritionsource.hsph.harvard.edu/healthy-weight/best-diet-quality-counts/
Khan, Marzia. Nutrigenomics: How Your Genes Influence Your Nutritional Needs and Health. Jan. 2024, https://www.news-medical.net/health/Nutrigenomics-How-Your-Genes-Influence-Your-Nutritional-Needs-and-Health.aspx
Lawton, Graham. There is no perfect diet that works for every metabolism or body type. June 2020, https://www.newscientist.com/article/2246056-there-is-no-perfect-diet-that-works-for-every-metabolism-or-body-type/
Zoppi, Lois. Genetic Factors Impacting Nutritional Requirement. Oct. 2018, https://www.news-medical.net/health/Genetic-Factors-Impacting-Nutritional-Requirement.aspx#