Pros and Cons of Trendy Diets and Weight Loss

By Emily Gerrets, LWDI Intern

Weight loss is a huge trend in today’s society. Many popular diets continue to be created to help people achieve this goal. “Trendy” diets can be harmful for those who don’t have all the information before they start. Diets that claim to aid in weight loss can long-term side effects on those participating. This blog focuses on a few of those trending diets, gives a little background information, and provides pros and cons for each of them. Before starting any new diet, people should speak with their Registered Dietitian or Doctor to make sure that diet is safe for them and won’t cause any harm, especially if the person has a condition such as diabetes or heart disease.

Keto Diet

The ketogenic diet or “keto” diet is high in fat, low in carb and moderate in protein. This diet has been said, by some, to produce benefits such as help managing diabetes, improving epilepsy and Alzheimer’s, and aid in weight loss. The diet works by severely restricting carbohydrate (carb) intake, which is the main source of energy for the body. When carb intake is restricted it forces the body to use fat as an energy source. When fat is broken down it makes ketones, this is why the diet is called the “ketogenic” or “keto” diet.

Some short-term side effects could include flu-like symptoms, trouble sleeping, and constipation. Those participating in this diet should be aware of long-term effects including kidney stones, liver disease, and nutrient deficiencies. Studies have also shown that the high fat (specifically saturated fats) nature of this diet could increase the risk for heart disease and other heart problems. 

For more than a hundred years, the keto diet has been used to help manage Epilepsy, a seizure disorder. Currently, the long-term effects are being researched as well as how it affects those with diabetes or obesity1. For example, there could be a higher chance of hypoglycemia in those on an insulin regimen2. In obese patients, a high protein and high fat diet could raise LDL cholesterol levels (the “bad” cholesterol) causing heart problems. 

Carnivore Diet

The carnivore diet consists of only meat and animal products and excludes all other foods. It has been said to help with weight loss, mood problems, blood sugar problems, and others. However, there is not enough research to support these benefits.  There is also little research done on the long-term complications that could occur with this diet.

Because this diet excludes fruits, grains, and vegetables, nutrient deficiencies are likely to occur. Negative effects of this diet could include heart problems and a higher risk for heart disease because of the increased saturated fat and cholesterol. 

Constipation could be caused by this diet due to its excluding of foods high in fiber such as fruits, vegetables, and grains3.

Whole 30

Whole30 is a 30-day diet plan designed to promote “clean-eating” by cutting out certain food groups. The food groups that are eliminated include: sugar, artificial sweetener, alcohol, grains, beans or legumes, soy, dairy, and processed foods. This leaves meat, poultry, fish, vegetables, fruit, and fats. 

The diet’s claims include weight loss, improvement in health conditions such as headaches, digestive problems, clear skin, and energy levels among others. The creator of Whole30 says she chose 30 days because “thirty days is a good compromise. It takes 66 days for a habit to stick, but if we told someone to do this plan for that long, it’d be pretty intimidating”- Hartwig.

A few benefits of this diet are that participants don’t have to count calories, they shouldn’t feel as hungry as they normally would, and there isn’t a point system for participants to follow. Some negative notes of this diet are that it is a very restricted diet, it can be hard to follow in a social setting, and also participants will be required to do meal preparation which can be time consuming4.


A paleo diet is based on the eating style of people during the paleolithic era. This era took place between 2.5 million to 10,000 years ago. The paleo diet includes foods that can be hunted or gathered such as: lean meats, fruits, vegetables, fish, nuts, and seeds. Dairy, legumes, and refined grains, therefore, are eliminated because they weren’t consumed during this time period. However, because of this stipulation, the diet can be restrictive making the diet difficult to follow.

The goal of this diet is to get humans to eat in a way that is closer to what their paleolithic ancestors ate. The reason for this diet is that it is believed that genetically, the human body does not work well with modern diets. This theory is called the discordance hypothesis. This hypothesis states that updates in farming changed people’s diets which caused the body to fall behind in adapting to these new dietary changes. This lack of adapting is believed to contribute to obesity, diabetes, and heart disease in today’s people5. This diet can potentially lead to weight loss, and improved health conditions. Some downfalls to this diet are that it is restrictive and that more research needs to be done to reveal any long-term side effects.

Although these diets all have their pros and cons, no one diet is perfect for everyone. Weight loss should be based on an individual level and ideally be done in the healthiest way possible. This may include involving health care workers such as Registered Dietitians, and Doctors, among others. However, if someone would want to try a new diet without consulting a medical professional, ample research should be done on the diet to avoid any negative results. It is crucial that participants find reputable sources when learning about a new diet to avoid finding false information. The Academy of Nutrition and Dietetics’ website is a great resource to find articles written by nutrition professionals. It is important to avoid any diets or products that state they cause quick weight loss because quick weight loss can be due to muscle, bone, or water loss and not fat which is what most people want to lose. Other diet/product claims to be avoided are restrictive diets and strict meals. Restrictive diets are difficult to follow and hard to make a long-term way of eating. Strict meals can become repetitive and boring which makes participants lose interest. It is also not realistic for people to consume the same meals on a daily basis6. Popular diets can be very intriguing for those who are trying to lose weight; however, participants should be mindful that they are not always the safest or healthiest option for everyone.

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  1. Gordon, Barbara. “What Is the Ketogenic Diet.” EatRight, 
  2. Adam, Felman. “Ketogenic Diet for Type 2 Diabetes: Side Effects, Benefits, and Alter.” Edited by Natalie Olsen, Medical News Today, MediLexicon International, 29 Mar. 2019,,hypoglycemia%20(low%20blood%20sugar). 
  3. Streit, Lizzie. “All You Need to Know About the Carnivore (All-Meat) Diet.” Healthline,
  4. Webber, Jamie. “Whole30 Diet Made Simple – Food List and Rules for Beginners.” Greatist, Greatist, 27 Sept. 2019, 
  5. Mayo Clinic Staff. “Paleo Diet: Eat like a Cave Man and Lose Weight?” Mayo Clinic, Mayo Foundation for Medical Education and Research, 25 Aug. 2020, 
  6. “Staying Away from Fad Diets.” Edited by Taylor Wolfram, EatRight, 18 Mar. 2019, 

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