In a study of more than 2,000 overweight individuals with pre-diabetes who followed a low-calorie diet for eight weeks, men lost significantly more body weight than women, and they had larger reductions in a metabolic syndrome score, a diabetes indicator, fat mass, and heart rate. Women had larger reductions in HDL-cholesterol, hip circumference, lean body mass - or fat free mass - and pulse pressure than men.
"Despite adjusting for the differences in weight loss, it appears that men benefited more from the intervention than women,” says lead author Dr. Pia Christensen of the University of Copenhagen, in Denmark. “Whether differences between genders persist in the long-term and whether we will need to design different interventions depending on gender will be interesting to follow. However, the eight-week, low-energy diet in individuals with pre-diabetes did result in the initial 10 percent weight loss needed to achieve major metabolic improvement in the first phase of a diabetes prevention program."
An estimated one out of three American adults lives with higher than normal blood sugar levels known as prediabetes, according to the Centers for Disease Control and Prevention. Researchers from the University of Missouri School of Medicine recently found that while men may lose more weight on low-carb diets, women actually see better improvements in artery flexibility. It's a finding that may help pre-diabetic women reduce their risk for heart disease through a low-carb diet.
"Previous research has shown that as women age, their blood vessels stiffen more so than men, putting them at an increased risk of heart disease," says Elizabeth Parks, Ph.D., professor of nutrition and exercise physiology at MU. "Contrary to what you may think, you actually don't want stiff blood vessels. Rather, you want flexible vessels that expand slowly as the blood flows through them. Our study found that low-carb diets helped reduce the stiffness of arteries in women, which can, in turn, reduce their risk of developing serious heart conditions."
To illustrate this, Parks compares good vessels to be like a rubber hose and aging-causing vessels to become stiff, similar to a plastic pipe. When you pour water through a rubber hose, the hose bends and flexes as the water makes its way through. When you pour water through a solid pipe, the water travels through the pipe quickly. In the human body, for good health, we want flexible, pliable, resilient arteries. As part of the study, 20 middle-aged, pre-diabetic men and women were given carb-restricted meals provided by the MU Nutrition Center for Health for two weeks and were supplied meal planning instructions for an additional two weeks. Over the four-week period, the men in the study lost 6.3 percent of their body weight, while women lost 4.4 percent. However, using an arterial stiffness measurement called pulse wave velocity, the women showed reduced blood flow speeds of one meter per second, while men showed no changes in blood flow speed.
"Vascular stiffness is a natural process of aging that can be accelerated by obesity, insulin resistance and metabolic syndrome," said Parks, who also serves as associate director of the MU Clinical Research Center. "Our study is the first to demonstrate that weight loss can reduce arterial stiffness in as little as four weeks and that dietary carbohydrate restriction may be an effective treatment for reducing aortic stiffness in women."
Where Do Three Popular Weight-Reduction Plans Fit In?
More than 35 percent of American adults are considered obese, according to data from the Centers for Disease Control and Prevention. With so much emphasis put on weight and healthy living, many people turn to “quick-fix” or fad diets that promise rapid weight loss and a new waistline in a short amount of time. Some of the current popular mainstream diets shouldn’t be considered fads at all, says UAB Department of Nutrition Sciences Assistant Professor Amy Goss, Ph.D. “Instead, they are more of a lifestyle change that can lead to much healthier living.”
Established in 2009, the Whole30 program is thought of as a nutrition reset, according to the official program website. It is designed to help participants put an end to unhealthy cravings and habits, restore a healthy metabolism, heal the digestive tract and balance the immune system.
In a Whole30 diet, vegetables, fruits, and in moderation, unprocessed meats, seafood, eggs, certain oils and even coffee are allowed, although adding milk or sugar is discouraged. Prohibited foods include dairy, grains, alcohol, legumes, added sugar, MSG and “junk” food. “Whole30 can introduce new vegetables to people that they may not be familiar with, and learning how to prepare these new foods in different ways is one major plus with Whole30,” said UAB wellness specialist Riley Thornton, RDN. “It’s important to practice variety, moderation and balance in any diet.”
Goss sees only a few drawbacks to Whole30. “There’s likely no downside to trying Whole30 because you’re eating whole foods and eliminating alcohol, added sugars, processed carbohydrates and fats,” she said. “I wouldn’t discourage anyone from trying Whole30, but the primary connotation of Whole30 is that this diet is a temporary solution and lacks a strong scientific basis for eliminating some food groups. Diets like this can also be expensive.”
Similar to Whole30, the paleo diet focuses on the way our human ancestors used to eat - whole meat, fruits, vegetables and nuts. The diet recommends removing processed foods, grains, legumes, refined sugars, vegetable oils and dairy. “The paleo diet focuses more on primitive eating,” Thornton said. “It is very restrictive, and you may be missing out on a lot of your key food groups.”
Before diving into a ketogenic diet, Goss and Thornton recommend knowing about ketosis and what it does to the human body. Ketosis is a metabolic state in which fat becomes the body’s primary fuel source instead of the usual glucose, which is derived from carbohydrates. Typically, eating carbs triggers the release of the hormone insulin, which helps cells use glucose for energy.
A ketogenic diet is high in fat and low in carbohydrates, limiting them to 20 to 50 grams per day from foods like vegetables, which Thornton says is a low intake. When someone follows this method of eating, glucose levels remain steady, meaning there isn’t a surge of insulin. Conversely, the dietary or body fat is broken down into ketones or organic compounds. “The brain loves ketones because they are a good source of fuel,” Goss said. “Your muscles can metabolize the ketones, and your body can’t store them as fat - the biochemical pathway that leads to the production of ketones from the metabolism of fat is irreversible. Energy from ketones can’t be stored, so ketones are either used by tissues or excreted in the urine and breath. Many patients report feelings of high energy, and it’s possible they are compelled to be more active.”
Another health benefit from the ketogenic diet is that there is evidence that people suffering from Type 2 diabetes can wean off medication with a doctor’s supervision because the diet is low-carb. However, Goss says there may be metabolic health benefits from the ketogenic diet for the average person, adding that it suppresses the appetite and there is evidence to suggest that it prevents a steep drop in metabolic rates.
“Typically, there are physiological and metabolic adaptations that occur with weight loss during calorically restrictive diets including loss of lean, metabolically active tissues such as muscle and organ mass, resting metabolic rate declines,” Goss said. “Even during exercise there is an increase in muscle efficiency, meaning that, with the same amount of work, fewer calories are burned compared to a non-overweight person of the same body size. These adaptions all work to defend a person’s higher body weight and lower chances of maintaining the weight loss long term.”
Overall, Goss and Thornton recommend that any diet that has someone eating whole foods with balance and variety is a good diet; however, they caution people looking for that “quick fix.” “These three diets aren’t like the grapefruit diet in that they eliminate so many food groups, so it’s important to be wary of diets that do require those strict guidelines,” Goss said. “While the ketogenic, Whole30 and paleo diets aren’t convenience diets - and they can cause challenges for eating out and cause a strain on your wallet - they are providing whole food solutions rather than eating processed and junk food.”
Dieters who go vegetarian not only lose weight more effectively than those on conventional low-calorie diets but also improve their metabolism by reducing muscle fat, a study published in the Journal of the American College of Nutrition found. Losing muscle fat improves glucose and lipid metabolism so this finding is particularly important for people with metabolic syndrome and Type 2 diabetes, says lead author, Dr. Hana Kahleová, Director of Clinical Research at the Physicians Committee for Responsible Medicine in Washington, D.C.
Seventy-four subjects with Type 2 diabetes were randomly assigned to follow either a vegetarian diet or a conventional anti-diabetic diet. The vegetarian diet consisted of vegetables, grains, legumes, fruits and nuts, with animal products limited to a maximum of one portion of low-fat yogurt per day; the conventional diabetic diet followed the official recommendations of the European Association for the Study of Diabetes (EASD). Both diets were restricted by 500 kilocalories per day compared to an isocaloric intake for each individual.
The vegetarian diet was found to be almost twice as effective in reducing body weight, resulting in an average loss of 6.2 kilograms compared to 3.2 kilograms for the conventional diet. Using magnetic resonance imaging, Dr. Kahleová and colleagues then studied adipose - fat-storage - tissue in the subjects' thighs to see how the two different diets had affected subcutaneous, subfascial and intramuscular fat - fat under the skin on the surface of muscles and inside muscles. They found that both diets caused a similar reduction in subcutaneous fat. However, subfascial fat was only reduced in response to the vegetarian diet, and intramuscular fat was more greatly reduced by the vegetarian diet.
This is important as increased subfascial fat in patients with Type 2 diabetes has been associated with insulin resistance, so reducing it could have a beneficial effect on glucose metabolism. In addition, reducing intramuscular fat could help improve muscular strength and mobility, particularly in older people with diabetes. "Vegetarian diets proved to be the most effective diets for weight loss,” Dr. Kahleová said. “However, we also showed that a vegetarian diet is much more effective at reducing muscle fat, thus improving metabolism. This finding is important for people who are trying to lose weight, including those suffering from metabolic syndrome and/or Type 2 diabetes. But it is also relevant to anyone who takes their weight management seriously and wants to stay lean and healthy."
About The Author:
With over 30 years of writing and editing experience, Kevin Kerfoot writes about health, nutrition, skin care and oral hygiene for Trusted Health Products’ natural health blog and newsletters.