Macros may get all the attention, but these nutrients deserve some credit too.

Carolyn Williams, Ph.D., R.D.
August 05, 2020
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Most weight-loss diets have one thing in common: They focus on counting or limiting macros—the carbs, protein and fat eaten—using different approaches as a way to guide food choices and to control caloric intake. This logic stems from the fact that macros (short for macronutrients) are the only nutrients that have calories. But does this mean other nutrients—ones without calories, like certain vitamins and minerals—have no real impact on weight loss? Not at all.

Losing weight is not an easy process, and your body feels the same! In fact, shedding fat is a pretty complicated process for the body when you consider all the metabolic, biochemical and physiological reactions that must occur. And since reactions usually require enzymes, this is where several vitamins and minerals can impact weight loss. But there are also nutrients, whose connection to weight we know less about, that research associates with greater weight loss and healthier body weights. This suggests that focusing on some key nutrients, along with macros, is your best bet when dieting.

Check out these top nutrients needed for weight loss, along with some of the best places to get them!

1. Magnesium

Recipe pictured above: Blueberry-Cashew Granola Bars

Over 300 different enzyme systems need magnesium for reactions to occur, including ones involved in metabolism and glucose regulation, and research suggests a direct connection between insulin resistance and magnesium intake. Insulin resistance can complicate weight loss for many, because high levels of blood sugar can end up being stored as fat. However, research suggests that consuming adequate magnesium each day can slowly decrease insulin resistance and may serve as a key weight-loss plan component.

Best Sources of Magnesium (Daily Value for magnesium is 420 mg):

  1. Nuts such as almonds, cashews and peanuts: a 1-ounce serving has 63-80 mg
  2. Soymilk: 1 cup has 61 mg
  3. Cooked spinach: 1 cup has 78 mg
  4. Legumes such as black beans and edamame: a ½-cup serving has 50-60 mg

2. Vitamin D

Until about 15 years ago, vitamin D intake wasn't a real concern. We thought sunlight triggered adequate production in most people, and its primary role was bone health. Today, data suggests that a majority of the population has insufficient levels, vitamin D's role in a variety of health issues is a hot area of research and low levels of vitamin D are considered a risk factor for obesity and obesity-related diseases. Vitamin D's connection to body weight isn't fully understood, but low levels of vitamin D are also linked to chronic inflammation. (P.S. Inflammation could be the reason you're not losing weight—here's what to do about it).

Regardless of the mechanism, most of us could benefit from more vitamin D, and some studies have even suggested that supplementing vitamin D may increase loss of body fat. Not many foods are rich sources of vitamin D, so this is one nutrient that many health professionals suggest supplementing to meet your daily needs.

Best Sources of Vitamin D (DV for vitamin D is 20 mcg or 800 IUs):

  1. Cod liver oil: 1 Tbsp. has 34 mcg
  2. Trout or salmon: a 3-ounce serving has 14.2-16.2 mcg
  3. UV-exposed mushrooms: a ½-cup serving has 9.2 mcg
  4. 2% milk: 1 cup has 2.9 mcg
  5. Fortified plant-based milk: 1 cup has 2.5-3.6 mcg

3. Vitamin C

Recipe pictured above: Philly Cheesesteak Stuffed Peppers

More commonly touted for improving immunity and preventing disease, vitamin C isn't often associated with weight loss. But because it's an antioxidant, vitamin C is even more important when people who are overweight or obese are trying to lose weight. This is because even small increases in weight can trigger inflammation, which in turn increases production of free radicals. This leads to a cascade of hormonal and metabolic effects (such as insulin resistance) that may encourage more weight gain.

Meeting antioxidant needs is crucial for stopping inflammatory-related weight gain, and research suggests that overweight individuals have higher needs due to greater free radical production. Vitamin C is one of the most important nutrients to consume, yet data suggests most of us don't meet our daily recommendations.

Best Sources of Vitamin C (Daily Value for vitamin C is 90 mg):

  1. Red bell pepper: a ½-cup serving has 95 mg
  2. Orange: one medium orange has 70 mg
  3. Kiwi: one medium has 64 mg
  4. Cooked broccoli: a ½-cup serving has 51 mg
  5. Sliced strawberries: a ½-cup serving has 49 mg
  6. Cooked Brussels sprouts: a ½-cup serving has 48 mg
  7. Grapefruit: one half of a grapefruit has 39 mg

4. Carotenoids

Carotenoids are a family of biologically active compounds that include beta carotene, lycopene and lutein, and they give certain fruits and vegetables their red, orange and yellow coloring. One study compared phytochemical intake to body weight and found that higher intakes of carotenoid-rich foods were associated with lower body weights in participants. Additionally, as BMI increased, carotenoid intake decreased. Yet no significant differences in calorie intake were noted between the groups.

This could be due to several things, the most obvious of which is that people at healthy weights likely ate more fruits and vegetables. But researchers think the antioxidant activity of carotenoids also plays a role by reducing inflammation. This is because systemic inflammation is associated with hormonal imbalances and insulin resistance, two effects that promote weight gain, not weight loss. So it seems loading up on carotenoid-rich food may promote weight loss, along with stopping free radicals that could trigger cancer and other diseases.

Best Sources of Carotenoids (There is no DV for carotenoids, but these carotenoids are a form of vitamin A found in plants. The Daily Value for Vitamin A is 900 mcg RAE).

  1. Baked sweet potato: 1 medium has 1,403 mcg
  2. Mashed pumpkin: 1 cup has 705 mcg
  3. Raw carrots: ½ cup has 459 mcg
  4. Cantaloupe: ½ cup has 135 mcg
  5. Red bell pepper: ½ cup has 117 mcg
  6. Mango: 1 medium has 112 mcg

5. Iron

Recipe pictured above: Broccoli Rabe with Cannellini Beans

Adequate iron stores enable hemoglobin in red blood cells to carry oxygen to cells throughout the body. But when iron stores and levels are low, red blood cells aren't able to deliver oxygen which impairs cells' ability to metabolize energy. Iron-deficiency anemia develops when this continues, and common side effects are pale skin, fatigue and sensitivity to cold temperatures. This lack of oxygen may also impede weight loss in some individuals. In fact, a 2014 study suggested that treating this type of anemia with iron supplementation resulted in improvements in hemoglobin levels, but also decreases in body weight, waist measurements and BMI.

Anemia isn't always due to a lack of iron, and there can be side effects from taking iron if not needed. Because of this, focus on foods first. Then, if needed, see your doctor to determine next steps. (P.S. When possible, try to pair your iron-rich recipes with foods high in vitamin C to increase absorption!)

Best Sources of Iron (Daily Value for iron is 18 mg):

  1. Fortified breakfast cereals: 1 serving has 18 mg
  2. Legumes such as white beans, kidney beans and chickpeas: 1 cup has 4-8 mg
  3. Dark chocolate: a 1½-oz. serving has 3.5 mg
  4. Tofu: ½ cup has 3 mg
  5. Cooked lentils: ½ cup has 3 mg
  6. Braised beef round: 3 oz. has 2 mg

6. Probiotics & Prebiotics

Recipe pictured above: Creamy Blueberry-Pecan Oatmeal

Good bacteria play a role in the digestion of fiber and fatty acids. Because of this, research suggests that one's gut health may impact how efficient a body is at shedding excess weight. In addition, having a diverse supply of beneficial microbes is also good when it comes to reducing inflammatory compounds that can lead to insulin resistance and weight gain.

Additionally, some research suggests that certain strains within the Bifidobacterium and Lactobacillus species may aid in weight loss. This means strengthening the gut's microbe barrier is not only key for overall health, but also for a healthy body weight—and one of the best ways to do this is to consume probiotics (or food containing live bacteria cultures) and prebiotics (or fibrous foods that gut bacteria need to thrive).

Best Foods to Get Probiotics & Prebiotics (no Daily Value or official intake recommendation):

  1. Yogurt and nondairy yogurt
  2. Kefir
  3. Sauerkraut
  4. Kombucha
  5. Miso
  6. Tempeh

7. Zinc

Over 10 years ago, researchers noticed that overweight and obese individuals often had lower intake and blood levels of zinc, and data now suggests that diets low in zinc are a risk factor for weight gain and obesity. While the connection and causal relationship between zinc and body weight isn't fully understood, increasing zinc intake appears to improve insulin resistance (a condition, as mentioned above with magnesium, that can stall weight loss) and regulate appetite.

Now, several studies also suggest higher zinc intake may facilitate greater reductions in weight and body size when dieting. One of the more recent examined the effects of zinc supplementation while following a lower-calorie diet, and the group taking zinc reported significantly higher weight loss and decreases in BMI and waist and hip circumferences. And while this particular study increased intake using a supplement, zinc is widely available in both animal- and plant-based protein foods.

Best Sources of Zinc (Daily Value for zinc is 11 mg):

  1. Cooked oysters: a 3-oz. serving has 74 mg
  2. Cooked beef, roast or ground: a 3-oz. serving has 5.3-7 mg
  3. Crab and lobster: a 3-oz. serving has 3.4-6.5 mg
  4. Fortified breakfast cereal: a serving has 2.8 mg
  5. Seeds and nuts, like pumpkin seeds and cashews: a 1-oz. serving has 1.6-2.2 mg

Carolyn Williams, Ph.D., RD, is author of the new cookbook, Meals That Heal: 100 Everyday Anti-Inflammatory Recipes in 30 Minutes or Less, and a culinary nutrition expert known for her ability to simplify food and nutrition information. She received a 2017 James Beard Journalism award. You can follow her on Instagram @realfoodreallife_rd or on carolynwilliamsrd.com.