With the new year comes the desire for new beginnings and a fresh start. We may hear our friends, coworkers and family talk about new diets they're planning to try.

We also see countless Facebook articles about the latest eating trends and weight-loss strategies, and with all this conflicting information it can become difficult to know what we should even be eating.

Ultimately, there are benefits and drawbacks to every diet, so let's cut through all the noise and go straight to the pros and cons of some of the most popular ones.

The keto diet

Restricted foods: beans, bread, rice, pasta, sweets, potatoes, corn, many fruits, milk

The pros of the keto diet:

• Can reduce hemoglobin A1c and blood glucose¹
• The restriction of many food groups may lead to weight loss²
• May increase HDL cholesterol (the good kind) and reduce triglycerides¹
  
  

The cons to the keto diet:

• Restricts many foods, making it difficult to sustain²
• Cannot "cheat" — this will take you out of nutritional ketosis and may lead to detrimental swings in blood sugar and lead to blood vessel damage³
• Can increase LDL cholesterol²
• May be difficult to obtain certain nutrients²
  
  

The paleo diet

Restricted foods: grains, beans, cheese, milk, peanuts, soy foods (including tofu), processed foods, artificial sweeteners, refined sugars, some oils

The pros of the paleo diet:

• Focuses on many nutritious, unprocessed foods like fruits, veggies and proteins⁴
• The restriction of many food groups may lead to weight loss⁴
• May provide beneficial nutrients like vitamin C, potassium and fiber
  
  

The cons of the paleo diet:

• Restricts nutrient and fiber rich foods such as beans and whole grains⁴
• Prohibits prominent cultural foods such as rice and lentils⁴
• Research is inconclusive on whether it helps people with type 2 diabetes¹
• May be difficult to obtain calcium for bone health⁴
• Can be expensive⁴
  
  

The Whole30

Restricted foods: grains, beans (except peas), cheese, milk, peanuts, soy foods (including tofu), artificial sweeteners, added sugar, some oils, alcohol, honey, maple syrup and even treat foods made with approved ingredients

The pros of Whole30:

• Focuses on nutrient rich whole foods like veggies, fruits, and proteins
• Allows people to mindfully add foods back into their diet after a 30 day period⁵
• Following the diet's protocol for 30 days may lead to weight loss due to the restriction of many foods
  
  

The cons of Whole30:

• Very restrictive, which may make eating out or socializing difficult
• May be difficult to get adequate calcium for bone health
• Restricts many cultural foods
• May be time intensive due to food label reading, meal planning and meal prep⁵
  
  

Whole30 also recommends limiting snacking.⁵

The whole foods, plant-based diet

Restricted foods: meat, poultry, dairy, eggs, cooking oils, juices, refined grains (white bread, pasta and rice)

The pros of a whole foods plant-based diet:

• Focuses on nutrient and antioxidant rich veggies, fruits, beans, grains and nuts⁶
• Restricts many foods, which may lead to weight loss⁷
• Shown to reduce blood pressure and LDL cholesterol⁶
  
  

The cons of a whole foods, plant-based diet:

• Highly restrictive, making it difficult to eat out or at social gatherings
• May be difficult to get enough omega-3 fats, protein, vitamin B12, zinc, iodine and calcium⁷
• Requires knowledge and deliberate meal planning to obtain all the necessary nutrients⁷
  
  

Intermittent fasting

Restricted foods: practice fasting days or reduce the timeframe for eating, rather than the restriction of specific foods

There are many different intermittent fasting protocols, with some lacking support from scientific research.⁸

The pros of intermittent fasting:

• No restricted foods
• May improve glucose control and insulin resistance⁸
• May lead to weight loss⁸
  
  

The cons of intermittent fasting:

• May lead to intense hunger and side effects like fatigue, irritability and difficulty concentrating⁹
• Can lead to overeating during the time frame when eating is allowed⁹
• Does not purposefully encourage nutritious foods like veggies, fruits and proteins
  
  

Juice cleanses

Restricted foods: typically, all foods except juices and maybe a few foods containing protein

The pros of a juice cleanse:

• Veggie and fruit juices can contain antioxidants and vitamins¹⁰, such as potassium, vitamin C and Vitamin K
  
  

The cons of a juice cleanse:

• Resulting weight loss will likely be from losing water weight, a lack of food in the GI tract and muscle loss
• Will likely result in a shortfall in many nutrients¹⁰ including protein, fat, B vitamins and calcium
• Juicing removes much of a fruit or vegetable's fiber¹⁰
• Can lead to hunger and fatigue¹⁰
  
  

So, which diet is best?

The major drawback of almost all of these diets is that they are very restrictive and difficult to sustain. While they are achievable for some time, almost all of us will encounter situations such as ordering takeout from a restaurant and busy schedules that wear away at our intentions.

What's important for anyone considering a diet to know is that losing a few pounds, stopping the diet, regaining the weight and restarting a few months later can lead to an unhealthy behavior pattern known as yoyo dieting or weight cycling. This is detrimental to our bodies because it leads to muscle and potentially bone loss.

Another major drawback is that many of these diets restrict entire food groups, making it difficult to obtain certain essential nutrients. For example, it may be hard to get enough calcium when following the whole30 or paleo diet as they restrict dairy foods and most grocery store almond milks.

Ultimately, trying a new diet every year that just ends up in regaining the weight we lost can take a toll on our mental health, too. Oftentimes, we may overeat when we finally allow ourselves to enjoy those diet-restricted foods again, feel guilt after doing so and then experience low self-esteem. But let me tell you — it is the diet, not you!

If you do decide to try one, first let your doctor know and consider meeting with a registered dietitian who can help make sure the diet is right for you and you get all the nutrients you need. Some medical conditions and medications make these diets unsafe, and none of these diets are appropriate for people with a history of an eating disorder, or, in my opinion, pregnant women.

Sources:

• ¹Nutrition therapy for adults with diabetes or prediabetes: a consensus report
• ²Advantages and disadvantages of the ketogenic diet: a review article
• ³Short-term low-carbohydrate high-fat diet in healthy young males...
• ⁴Cutting through the paleo hype: the evidence for the paleolithic diet
• ⁵The Whole30 Program Rules
• ⁶Evaluation of an eight-week whole-food plant-based lifestyle modification program
• ⁷Nutrient and food intake of participants in a whole-food plant-based lifestyle program
• ⁸The effectiveness of intermittent fasting to reduce body mass index and glucose metabolism...
• ⁹Potential benefits and harms of intermittent energy restriction and intermittent fasting...
• ¹⁰Body cleansing or nutrient depleting?