Did you know that many popular diets come with a risk of nutritional deficiencies? If you are considering jumping into a new eating plan, read this first. Here is an overview of some of the most important supplements to consider if you’re trying out a new nutritional plan in 2020. 


The ketogenic diet, or “keto” for short, is hugely popular right now. Everywhere you look there are cookbooks, blogs, and meal kits. Keto seems to be everywhere. But what is it and why is it so popular? 

Originally developed to treat children with epilepsy, the ketogenic diet has more recently been adopted as a weight-loss diet. It has also been suggested to help manage diabetes and ward off Alzheimer’s disease. 

In this diet, fat is the main source of calories, followed by moderate protein and a very small amount of carbohydrates. With carbs limited to 50 grams or less per day, keto dieters typically cut out all bread, grains, and cereals, and even most fruits and starchy vegetables. The idea is that while the human body typically burns carbs for energy, the keto diet restricts carbs so much that your body has no choice but to turn to burning fat for fuel. 

The process of burning fat instead of glucose for fuel is called ketosis, hence the name of the diet. The transition to ketosis usually takes about a week to ten days and can bring on some nasty side effects sometimes referred to as the “keto flu” including headache, fatigue, nausea, brain fog and difficulty sleeping.

While burning fat for fuel sounds like a great way to lose weight, it can be difficult to maintain, so most people do not end up following a true ketogenic diet for very long. There are also no long-term studies available to prove safety or efficacy. Maintaining a strict ketogenic diet is difficult and is best done with the guidance and weekly monitoring of a dietitian.

Because of the restrictiveness of the keto diet, it may put you at risk for deficiencies in micronutrients including seleniummagnesiumphosphorusironcalcium and vitamins Dand C. A good way to ensure you are addressing any and all deficiencies while avoiding added starches or sweeteners is to look for a targeted keto multivitamin. You may also want to add probiotics and a fiber supplement because of the limited amount of high-fiber foods like fruits, legumes and whole grains in the diet. 

The ketogenic diet is not recommended for people with pancreatic disease, liver conditions, thyroid problems, eating disorders or a history of eating disorders, pregnant women, or those with gallbladder disease or who have had their gallbladder removed. As previously stated, working with a dietitian for this type of diet is highly recommended. Please consult your doctor before beginning any kind of restrictive diet.


The vegan diet has been enjoying increased popularity thanks in part to celebrities and documentaries. While a vegan diet is not a fad diet in and of itself, some people jump into it on a whim without a proper plan in place and can quickly get into nutritional trouble. 

Going vegan means eliminating all meat, fish, poultry, dairy products, and eggs and eating a wide variety of fruits, vegetables, whole grainsnuts, seeds, and legumes. 

Some choose a vegan diet for moral reasons, citing the treatment of farm animals or the environmental impact of the meat and dairy industry. Others go vegan to lose weight, decrease their risk of chronic disease, manage type 2 diabetes or improve heart health. 

Whether you try a vegan diet for ethical reasons or for the myriad of health benefits, it’s important to plan well to make sure you’re eating a wide variety of whole foods. Simply cutting out animal products is not enough to reap the benefits of going vegan. 

Here are a few nutrients you should be paying special attention to:

  • Vitamin B12: Since vitamin B12 is only found in animal foods, every vegan needs to supplement in the form of vitamins or fortified foods such as cereals, soy milk or nutritional yeast.

  • Vitamin D: While it’s true that humans can convert sunlight into vitamin D, this is not the case all year round. Vegan sources of vitamin D include mushrooms (especially mushrooms exposed to sunlight), fortified plant-based milks, fortified tofu, fortified orange juice and vitamin D supplements.

  • Omega-3 fatty acids: When removing seafood from the diet, omega-3s can be replaced by consuming ground flaxseed, chia seeds, hemp seeds or walnuts. Try to include a variety of nuts and seeds in your diet each day. You can also choose to take a daily vegan omega-3 supplement.

  • Iron: Whole grains and beans are rich in iron but it isn’t as easily absorbed into the body as the iron in animal sources because it is bound by compounds called phytates. An easy way to combat this is by making sure to consume a source of vitamin C at the same time as you consume iron. The vitamin C boosts absorption by breaking the bond between iron and phytate. An example of this would be to combine chickpeas and broccoli or add red bell pepper.

Intermittent Fasting

Intermittent fasting is less of a diet and more of an eating pattern, cycling between blocks of time when you eat and when you fast (abstain from eating). Some of the benefits may include improved blood sugar levels, weight loss and maintenance, improved cognitive function, decreased inflammation and improved heart health.

When you hear about intermittent fasting, you may notice that there are a lot of variations. Here are a few of the most common types:

  • Alternate day fasting: On this plan, you fast every other day. On fasting days, you can drink water, black coffee or tea, but no food is permitted. On non-fasting days, you can eat whatever you want.

  • 16/8 diet: On this plan, you limit all food intake to one eight-hour block each day, then fast the other 16 hours. Many people who follow this plan skip breakfast and only eat lunch and dinner.

  • 5:2 fast: On this plan, you fast 2 days per week or eat a very small amount of calories (around 500) for each of those 2 days, then eat normally the other 5 days.

Whichever plan you choose (and there are a lot to choose from), you need to make sure you are starting from a healthy baseline (no nutrient deficiencies). You also need to make sure the food you consume during eating periods is nutrient-dense enough to meet all of your nutritional needs.

Intermittent fasting is not recommended for people with diabetes, women who are pregnant or breast-feeding and individuals with a history of eating disorders. Fasting for long periods of time is not recommended for women, as it may disrupt certain hormones. If you are considering fasting, you should first discuss it with a doctor, especially if you are on any medication.

When in Doubt, Eat Whole Foods

Many popular diets come with a risk of nutritional deficiencies. It is important to be aware of them so you can make adjustments accordingly. For most people, eating a variety of whole foods and getting regular exercise is the best path towards lifelong health. If you do want to try a more restrictive diet, consult a registered dietitian who can tailor a plan just for you and monitor your nutritional status along the way.