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Are fad diets healthy?

Fad diets tend to gain a huge following through social media sites such as blogs, Pinterest, Facebook, or Instagram. However, those who tend to talk about their experience or promote fad diets usually do not have any research-based facts to back-up their findings. Rather, they use their personal experience which can be harmful advice to others. Currently, two popular fad diets in the media are the Keto diet and intermittent fasting. So the question resides, are these fad diets healthy?



I am going to provide a quick overview, using the research, to help identify the health benefits and possible negative effects of the Keto diet and intermittent fasting.

The Keto diet has a lot of controversy with recent studies. This diet was originally created to help people who suffer with epilepsy because the ketogenesis state allows for neuron synapses to fire slower. The Keto diet is the consumption of high fats and low carbohydrates, allowing for a high probability of a caloric deficit. It can be easier for someone to eat a lot less of a high fat food, such as steak, rather than high carbohydrate, like pasta. A general guideline to reach ketosis would having a diet consist of 57% fat, 15-25% protein, and 5% carbohydrates.

Once the body has an insufficient amount of carbohydrates, it will resort into turning fat into glucose. Fat is oxidized by an enzyme called pyruvate that turns it into ketone bodies. These ketone bodies are then used as energy, rather than the glucose that would have been absorbed from carbohydrates. This oxidation of fat being used for energy causes weight loss, which is why this diet is so popular. Having the body solely run off of ketone bodies for energy is difficult to sustain due to some long term effects.

(https://www.nature.com/articles/ejcn2013116)


A large issue that some people run into is that the weight loss can be unsustainable. The body uses carbohydrates as its main energy source. Without carbohydrates, the brain can become less receptive and have a lack of energy. Many studies show that athletes on the Keto diet tend to have less motivation to exercise. As mentioned before, this diet was used to treat patients with epilepsy to slow down their neurotransmitters. This entails that when the body is in ketogenesis, it will ultimately slow down the body and alter mood and cognition. (https://europepmc.org/abstract/med/8589783)


Another diet that seems to be trending on my social media feed is intermittent fasting. Intermittent fasting can be any length of time, whether its 4 to 12 hours of fasting, as long as your body goes into starvation mode. One of my colleagues was telling me about this as this diet is actually a part of her religion. As a part of the Islamic tradition, for a month Muslims will not eat or drink anything during the daylight hours. There are many forms of intermittent fasting, but this is just an example. Another example of this could be only eating from 8am to noon. Intermittent fasting entails that there are set hours of the day dedicated to not consuming anything. This diet is intended to get the body used to being in a caloric deficit, ultimately losing weight. A common length of time people use to see results is fasting for 16 hours everyday while leaving an 8 hour window open to consume.

(https://link.springer.com/article/10.1007/s40279-015-0408-6 )

The concept of intermittent fasting allows for the body to go into starvation mode, releasing glucagon. This taps into stored energy, fat or muscle, so that the body can remain functioning. This means that body weight tends to go down because it is in a caloric deficit. Many studies show other health benefits such as less risk of cardiovascular disease, diabetes, increased gut motility, and decreased blood pressure. Again, with all of these benefits come with some risks such as dehydration and unsustainable weight loss.

(http://www.ncbi.nlm.nih.gov/entrez/query.fcgicmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=15741046)


Both the ketogenic diet and intermittent fasting have their pros and cons, but it all boils down to what works best for your body. These diets should not be attempted until consulting with a doctor and Registered Dietitian. These diets might be dangerous considering an individual's state of medical history, medication, hormone levels, etc. Honoring your hunger cues and adapting to your own lifestyle habits is essential as every person is different. The next time you are scrolling through your social media, be sure to educate yourself on the benefits and risk factors of the next diet.