Everyone wants to know how to lose belly fat or what foods to eat to help shrink waist size. Now a new study has found that eating "good carbs" may help us do just that. According to research published in The Journal of Nutrition, eating three servings of whole grains a day has been linked to smaller waist sizes in middle-aged adults. The study also found that a diet high in whole grains and low in refined carbs is associated with lower blood sugar, lower blood pressure, better cholesterol and fewer triglycerides in the bloodstream, all health markers.

To quote from the authors' conclusion: "Among middle- to older-age adults, replacing [refined grains] with [whole grains] may be an effective dietary modification to attenuate abdominal adiposity, dyslipidemia, and hyperglycemia over time, thereby reducing the risk of cardiometabolic diseases."

How eating good carbs help us reduce our waist size and get healthier

The key is knowing exactly what constitutes healthy carbs, and not confusing whole grains with highly processed foods, which have had most of the nutrients and natural fiber stripped out of them. Get it right, the study indicates, and you could enjoy carbs, a smaller waist size, and lower your lifetime risk of heart disease.

Americans' average waist size has been rapidly increasing, along with their risk of chronic diseases. In 2015-2016 the age-adjusted mean waist circumference was 40.2 inches for men and 38.6 inches for women, several inches larger than 15 years prior. These measurements exceed what the Centers for Disease Control and Prevention recommend.

Meanwhile, the pandemic has not been kind to our waist size or our weight profiles. A recent Harris Poll survey found that 42 percent of Americans gained weight during the pandemic, and the average weight gain among that group was 29 pounds. Among the gainers, 50 percent put on more than 15 pounds and 10 percent gained 50 or more pounds.

As we gain weight, our body stores some of it as belly fat, which over time becomes more resistant to being burned off, research has found. University of Sydney researchers studied the effects of intermittent fasting and found that "fat around the stomach, which can accumulate into a ‘protruding tummy’ in humans, was found to go into ‘preservation mode’, adapting over time and becoming more resistant to weight loss."

Smaller waist size and total body fat percentage have been shown to be reliable health indicators, which is why striving to reduce waist size is more than just a matter of fitting into your clothes better. It's a health goal since waist size is tied to diabetes, heart disease, high blood pressure, and other chronic conditions, according to the CDC, which recommends that men keep their waist size smaller than 40 inches and non-pregnant women 35 inches.

The average waistline grows as we age. Whole grain can slow that down

According to researchers at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, people who eat at least three servings of whole grains a day have smaller waist sizes than those who eat half a portion or less per day.

The study followed mostly white, middle-aged adults over 18 years to assess long-term risk factors for heart disease. The results showed that waist size increased by an average of over 1 inch for every four-year interval in the participants who ate few whole grains, and half that amount or 1/2 inch every four years in those who reported a high intake of whole grains. Furthermore, the low-grain group had significant increases in blood sugar levels and systolic blood pressure compared to those who ate more whole grains.

Eating fewer refined grains (packaged foods, such as chips, cookies, cereals, white bread, white rice, and boxed crackers) also led to lower increases in waist size and fewer triglycerides (fats in the blood), the researchers found. Therefore, making sure that the grains you are eating are whole and not refined is essential.

“Our findings suggest that eating whole-grain foods as part of a healthy diet delivers health benefits beyond just helping us lose or maintain weight as we age. In fact, these data suggest that people who eat more whole grains are better able to maintain their blood sugar and blood pressure over time. Managing these risk factors as we age may help to protect against heart disease” said Nicola McKeown, senior and corresponding author, in a press release.

The researchers believe there may be several reasons that whole grains may help people maintain their waist size and reduce their disease risk. Dietary fiber has a satiating effect and may help to avoid post-meal blood sugar spikes. Additionally, the vitamins, minerals, and antioxidants in whole grains may help lower blood pressure suggested Caleigh Sawicki, one of the study authors.

Whole grains also contain protein, which is additionally helpful in keeping you full and blood sugar steady.  For anyone who wants to get more protein, try adding the 10 Whole Grains With the Highest Protein Content, such as oats, buckwheat and quinoa.

How much and what type of grains should you eat?

According to the Dietary Guidelines for Americans 2020-2025, most Americans meet recommendations for total grain intakes, although 98 percent fall below recommendations for whole grains and 74 percent exceed limits for refined grains.

Furthermore, the guidelines note that half of Americans’ refined grain intake comes from foods such as sandwiches (white bread), pizza, and tacos and that another 20 percent comes from snacks and sweets including pretzels, cakes, and cookies, none of which are whole grains.

The USDA advises that the amount of grains someone needs to eat depends on their age, sex, height, weight, and level of physical activity. For women, the amount can also depend on if they are pregnant or breastfeeding.

For example, women need approximately 6-8 ounce equivalent, and men need about 6-10 ounce equivalents of whole grains per day. At least half of your total grains should be whole grains.

What are whole grains and how can we add them to our diet

Whole-grain foods are those grain-based foods –wheat, corn, rice, oats, barley, quinoa, sorghum, spelt, rye – that are eaten in their most whole or least processed form. A common belief is that eating carbs packs on belly fat, and many health-conscious adults make efforts to avoid them. However, this new study indicates that the more important decision is to make sure you're eating whole grains, not refined carbs.

The following are one-ounce equivalents of whole grains that people can include as part of a healthy diet:

  • 1 slice of whole-grain bread
  • ½ cup bulgur wheat, buckwheat, or barley
  • ½ cup cooked brown or red rice
  • ½ cup cooked quinoa
  • 1 cup low-sugar breakfast cereal
  • ½ cup cooked oatmeal
  • 2 rye crispbreads
  • 5 whole-wheat crackers
  • 1 small wholegrain chapati or roti
  • ½ cup cooked whole grain pasta

The benefits of whole grains include the fact that they are packed with fiber, B vitamins, and minerals which have additional health benefits such as regulating energy, boosting the immune system, and supporting healthy bones.

Including adequate whole grains and swapping refined products for whole-grain alternatives makes good sense for not only your waistline but your overall health and disease risk.

Bottom Line: Whole grains help avoid belly fat and expanding waist size

When choosing what kinds of carbs to eat, look for whole grains since a new study finds that eating more whole grains can reduce the growth of our waist size over time, as well as protect against heart disease, high cholesterol, and chronic conditions like high blood pressure.

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