The Do's and Don'ts of Your Diet Plan

If you're like most Americans and resolve to shed a few pounds by starting a diet in the new year, you've probably already planned what you're going to cut out.

Carbs? Meat? Dairy? Whatever your choice, eliminating certain food groups—as many fad diets do—could actually hurt your health. Here, you’ll learn about some of the most popular diets out there today and get tips for how to balance your daily food intake, so you don't miss out on the important stuff.

Remember, diets with claims that sound too good to be true are probably just that. Before changing how you eat in any major way, be sure to talk to your health care provider.

The Paleo Diet

If you like the idea of eating like a caveman—more whole foods, fewer processed ones—you might choose to follow a Paleo diet. It excludes dairy, grains, beans, sugar, potatoes and processed oils, like partially hydrogenated soybean oil. What can you eat? Meat, fish and shellfish, eggs, tree nuts, vegetables, fruit and canola and flaxseed oils are Paleo-approved.

What nutrients you might be missing

A Paleo diet can limit the amount of vitamin D, calcium, fiber, and healthy carbohydrates like whole grains and legumes. Carbohydrates are the main energy source for the cells in your body. They're especially important for your brain, since, unlike other organs in your body, it's completely dependent on carbs for normal functioning.

How to get them

Starchy vegetables like sweet potatoes and winter squash provide healthy carbs. Eat Paleo-approved foods like wild salmon and mushrooms for vitamin D, or consider a supplement. Salmon (or sardines) with bones provide calcium, too. Leafy greens, such as broccoli, kale and Chinese cabbage, and fortified almond milk are other good calcium sources. For fiber, make sure to eat a variety of fruits and veggies (fiber is found only in plant foods).

Vegetarian and Vegan Diets

Call them the anti-cavemen: Whether for ethical or for health reasons, vegetarians cut out meat, poultry and fish, and vegans eliminate all animal products, including eggs and dairy. Research shows a well-planned vegan diet can be good for weight control as well as overall health. Vegetarian and vegan diets tend to be high in fiber and are associated with lower cholesterol, decreases in heart disease and blood pressure, and lower risk of type 2 diabetes.

What nutrients you might be missing

When carefully planned, both of these diets are healthy and nutritionally adequate. Vegans could be at risk for insufficient omega-3 fats and vitamin B12 in their diets, though. Getting enough calcium is important, too.

How to get them

Both vegetarians and vegans need to make sure they have good sources of bioavailable calcium—found in calcium-set tofu (check the label for calcium sulfate), broccoli, bok choy, collard greens, kale and Chinese cabbage. To get omega-3 fats, consume walnuts and generous amounts of flaxseed and canola oils, and consider an algae-based (vegetarian) omega-3 supplement. For B12, vegans need to regularly consume B12-fortified foods, such as breakfast cereals and soy and rice beverages, or supplements. Vegetarians can rely on dairy and eggs for their B12.

Low-Carb Diet

A low-carb diet restricts carbohydrates such as those found in fruits, starchy vegetables, beans and refined and whole grains. These diets tend to help people drop weight quickly— eating fewer carbs dips your insulin levels and spurs the body to burn fat for energy, leading to weight loss. If you try a low-carb diet, choose foods with healthy unsaturated fats and healthy proteins. Eating a lot of saturated fats, which tend to come from animal products, can be bad for your health.

What nutrients you might be missing

Getting adequate dietary fiber—25 grams a day for women and 38 grams a day for men—can be a concern, as can vitamin C and folate. Also watch for added salt in processed and packaged foods.

How to get them

Non-starchy veggies like beets, asparagus, broccoli, eggplant and mushrooms increase fiber intake without piling on carbs. Seek tomatoes and tomato sauce, broccoli, red bell peppers and kiwifruit for vitamin C. Increase folate with asparagus, Brussel sprouts, avocado and spinach.

Gluten-Free Diet

Gluten is a protein found in foods containing wheat, barley and rye. While going gluten-free is a must for people with celiac disease, which causes severe symptoms when sufferers eat gluten and may interfere with the body's ability to absorb nutrients, skipping gluten has also become popular among people who want to eat healthier. But for those without gluten-related conditions, there’s little evidence that going gluten-free offers health benefits. To shed extra pounds, you’ll need to be mindful of your food choices and the amount you are eating.

What nutrients you might be missing

Whatever your reason for going gluten-free, you should know how it can affect your overall intake of certain nutrients. Since gluten-free products are made with refined starch and aren't enriched like wheat-based products, your gluten-free diet could be lacking in iron, folate and fiber.

How to get them

Get iron from meat, chicken, fish, beans and nuts. Consume a food high in vitamin C, such as an orange or red bell pepper, along with iron-containing foods to help with absorption. As a bonus, oranges and orange juice provide folate, too. Get fiber from fruits, vegetables, beans, nuts and non-gluten whole grains, such as brown rice, quinoa and oats.

And remember, just because a food is gluten free doesn't mean it's healthful or is a good choice for weight loss. Gluten-free diets that aren't carefully planned can be higher in salt, fat and sugar, since manufacturers compensate for flavor and texture problems in packaged gluten-free foods by adding these ingredients.

Diana Kelly is a New York City-based writer and editor with more than 10 years' experience covering health topics for women's and men's health websites. Follow her on Twitter, @DianaKelly, or check out her website, DianaKelly.com.

Reviewed by Shira Goldenholz, MD, MPH on December 23, 2014

Updated on December 18, 2019