Year after year, the top New Year’s resolution is to lose weight and eat healthier. And year after year, new and trendy diets emerge—often claiming life-changing effects. So are these diets revolutionary, or rubbish? Let’s break down four fad diets you’ll be hearing about a lot in 2018.


Because it restricts added sugars, grains, and dairy, the Whole30 diet encourages the consumption of fruits, nuts, and veggies.

At first glance, Whole30 looks similar to the Paleo Diet: you eliminate any food that wasn’t available to our cave-dwelling ancestors. That includes all sources of added sugar, grains, corn, rice, legumes, beans, dairy, alcohol, and certain additives like MSG and sulfites. These foods, according to proponents, may be negatively impacting your health by promoting inflammation, disrupting hormones, and messing with your microbiome. So what is allowed? Meat, seafood, poultry, eggs, vegetables, some fruits, nuts, seeds, and healthy oils.

Unlike the Paleo Diet, however, Whole30 only lasts 30 days. It’s an elimination diet, which means that you’ll eventually reintroduce the foods you gave up for 30 days, one at a time, so that you can identify any intolerances, sensitivities, or foods that just don’t make you feel your best.

The Pros:

Whole30 is a great way to identify any foods that might be causing distress, whether that’s decreased energy, breakouts, GI trouble, or mental fogginess. Because you’re getting rid of added sugar and alcohol, you’re all but certain to feel healthier—but you might also notice an improvement without other dietary culprits like dairy in your life. And because Whole30 automatically limits processed ingredients and promotes whole, nutrient-dense foods, it can be a great place to start if you’re interested in revamping your diet.

The Cons

The diet can be overly restrictive, even if it only lasts for a month, as many of the banned foods like grains, corn, rice, legumes, and beans can be perfectly harmless to your health. Plus, they can also be valuable sources of micronutrients like B vitamins, calcium, and vitamin D.

Ketogenic Diet

Under normal circumstances, our body prefers to burn carbohydrates for fuel, as it provides fast energy for our brain and muscles. But when you deprive your body of carbohydrates, as in the case of a ketogenic diet, your body turns to fat for fuel. When fats are broken down, the liver turns them into ketones, which can be used to generate energy. In this state, called ketosis, the body burns ketones as its primary source of fuel.

Right now, the ketogenic diet is only clinically indicated for the treatment or management of epilepsy and other seizure disorders. However, ongoing research is investigating its benefits with respect to metabolic disease, neurodegenerative diseases and brain injuries, weight loss, increased longevity, cancer protection, and improved athletic performance.

This high-fat, low-carb regimen means there’s plenty of room in your diet for avocado. Just don’t put it on toast!

What does the ketogenic diet look like? It’s comprised of 80% fat, 15% protein, and 5% carbohydrates, which means it’s very restrictive. You’ll build your diet around high-fat foods like avocado, olive oil, bacon, butter, cheese, and nut butters, supplementing with a small amount of meat, fish, poultry, seafood, and eggs. You can add very small amounts of non-starchy vegetables, but most dairy, fruits, grains, legumes, and starchy vegetables are off limits, as they have too many carbohydrates and will push you out of ketosis.

The Pros

Because of its severe carbohydrate restriction, a ketogenic diet may improve metabolic health and insulin sensitivity. Some studies have found that it can result in significant weight loss, although experts question the long-term sustainability of the diet.

The Cons

It’s very, very restrictive. In fact, eating just one potato chip may send you out of ketosis, negating all of its benefits in a single bite and leaving you feeling tired and sluggish for the 3 to 7 days it’ll take you to reach ketosis again. Furthermore, because you’re drastically limiting the whole food groups you consume, you may end up with micronutrient deficiencies.

Intermittent Fasting

Intermittent fasting generally refers to a dietary regimen that cycles between periods of eating and periods of fasting. There are several different versions of the diet, each with its own cadence of consumption and restriction.

Intermittent fasting places more importance on when you eat than what you eat.

Researchers have been studying the benefits of intermittent fasting for decades. Early animal studies found that prolonged caloric restriction resulted in increased lifespan and a reduced risk of chronic diseases including cancer, diabetes, and heart disease. Researchers theorize that our modern tendency to graze steadily throughout the day results in chronically high insulin levels, eventually leading to fat storage and insulin resistance. When you fast, however, insulin levels finally have a chance to drop. And it’s at this point that lipolysis, or the breakdown of fat, occurs. A drop in insulin also triggers the anti-aging mechanism known as autophagy, which helps your body clean out dysfunctional cellular debris.

The Pros:

Because you’re only monitoring when you eat rather than what you eat, no foods are off-limits. As a result, the diet is relatively low maintenance (no food journaling or counting calories here!). Some people find it beneficial in that it automatically restricts late-night eating, when they’re most prone to bingeing.

The Cons

The diet doesn’t emphasize quality or quantity of foods at all, which means you could theoretically eat pizza and ice cream to your heart’s content so long as it’s within your designated timeframe. And it’s not a magic pill to weight loss; most of the supposed benefits of intermittent fasting occur when you combine fasting with a diet full of nutrient-dense foods. And, of course, it’s inconvenient—navigating social events, from brunches to happy hours to a night on the town, can be difficult to follow when your eating and drinking period is so restricted.


For years, many blamed a host of GI symptoms—gas, bloating, stomach cramps, altered bowel function, and even fatigue—on gluten. Recent research, however, has suggested that gluten is not the culprit. Instead, a group of carbohydrates called FODMAPS (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols that are found in many gluten-containing foods) are to blame. In some, FODMAPS travel undigested to the intestines, where bacteria feed off of them, causing uncomfortable gas and bloating.

The Low FODMAP Diet is increasingly being prescribed to patients with symptoms of irritable bowel syndrome and other gastrointestinal complaints. Like the Whole30 Diet, it’s not a forever diet: the idea is to cut out all sources of FODMAPS for 3 to 8 weeks to see if symptoms subside. At the end of the elimination phase, you reintroduce each food one at a time to see how your body reacts. Eventually, you’ll be able to pinpoint which specific foods—and what amount of them—trigger symptoms.

Fructose should be avoided by those following a low FODMAP diet.

Where are FODMAPs found? The biggest sources are fructose, the sugar found in many fruits and vegetables; lactose, the sugar found in dairy products; fructan, found in wheat, rye, and other vegetables; galactans, found mostly in legumes; and polyols, found in fruits, vegetables, and sugar alcohols (for a more complete list of FODMAPs, click here).

The Pros:

For those with unidentifiable or intractable GI symptoms, a low FODMAP diet can be extremely helpful in identifying specific foods that exacerbate symptoms. Studies are certainly promising: on average, the diet shows improvement in 68-76% of patients. And because FODMAPs are found in many processed foods, it forces you to stick to a more balanced, whole foods based diet, which has health benefits beyond improved digestive health.

The Cons

The diet is extremely restrictive during the elimination phase, and it can be hard to stick to. This is especially true if you’re a vegetarian, since your main sources of protein, including beans, legumes, and some dairy, are off limits. The diet is also mainly for those suffering from IBS, so if you’re looking for improved health or weight loss, this probably isn’t the diet for you. And if you do have IBS, the diet can still be frustrating: many foods can trigger symptoms one day, but not the next; it’s certainly not a one-time cure.



Don’t forget to join our New Year, New You challenge for the chance to win more than $500 worth of health-oriented goodies, including a MyFitnessPal membership and an Apple Watch!

Kate Schlag

Posted by Kate Schlag

Kate Schlag, MPH, RD is the Nutritionist of Munchery. Kate Schlag is a Registered Dietitian and holds a Masters in Public Health with a concentration in nutrition from UC Berkeley’s School of Public Health. She completed her dietetic internship at Oregon Health & Science University and went on to begin her career as an outpatient dietitian at UCSF. Growing up in Boulder, Colorado shaped her preferences for healthy foods and fitness from an early age. As an athlete, she believes in fueling her body with healthy, wholesome foods to optimize her performance on the field and off. At Munchery, she works closely with the company’s culinary team to design healthy and balanced meals using fresh and whole ingredients, and is a resource of information about meals, ingredients, and general nutrition.

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