Tag Archives: Carbohydrates

Low-Carb, Higher-Fat Diets Add No Arterial Health Risks To Obese People Seeking To Lose Weight

OVERWEIGHT and obese people looking to drop some pounds and considering one of the popular low-carbohydrate diets, along with moderate exercise, need not worry that the higher proportion of fat in such a program compared to a low-fat, high-carb diet may harm their arteries, suggests a pair of new studies by heart and vascular researchers at Johns Hopkins.

Dr Kerry J. Stewart

“Overweight and obese people appear to really have options when choosing a weight-loss program, including a low-carb diet, and even if it means eating more fat,” says the studies’ lead investigator exercise physiologist Kerry Stewart, Ed.D.

Stewart, a professor of medicine and director of clinical and research exercise physiology at the Johns Hopkins University School of Medicine and its Heart and Vascular Institute, says his team’s latest analysis is believed to be the first direct comparison of either kind of diet on the effects to vascular health, using the real-life context of 46 people trying to lose weight through diet and moderate exercise.

The research was prompted by concerns from people who wanted to include one of the low-carb, high-fat diets, such as Atkins, South Beach and Zone, as part of their weight-loss program, but were wary of the diets’ higher fat content.

In the first study, presented June 3 at the annual meeting of the American College of Sports Medicine in Denver, the Johns Hopkins team studied 23 men and women, weighing on average 218 pounds (about 99 kg) and participating in a six-month weight-loss program that consisted of moderate aerobic exercise and lifting weights, plus a diet made up of no more than 30 percent of calories from carbs, such as pastas, breads and sugary fruits.  As much as 40 percent of their diet was made up of fats coming from meat, dairy products and nuts.

This low-carb group showed no change after shedding 10 pounds (4.5 kg) in two key measures of vascular health: finger-tip tests of how fast the inner vessel lining in the arteries in the lower arm relaxes after blood flow has been constrained and restored in the upper arm (the so-called reactive hyperemia index of endothelial function), and the augmentation index, a pulse-wave analysis of arterial stiffness.

Low-carb dieters showed no harmful vascular changes, but also on average dropped 10 pounds in 45 days, compared to an equal number of study participants randomly assigned to a low-fat diet. The low-fat group, whose diets consisted of no more than 30 percent from fat and 55 percent from carbs, took on average nearly a month longer, or 70 days, to lose the same amount of weight.

“Our study should help allay the concerns that many people who need to lose weight have about choosing a low-carb diet instead of a low-fat one, and provide re-assurance that both types of diet are effective at weight loss and that a low-carb approach does not seem to pose any immediate risk to vascular health,” says Stewart. “More people should be considering a low-carb diet as a good option,” he adds.

Because the study findings were obtained within three months, Stewart says the effects of eating low-carb, higher-fat diets versus low-fat, high-carb options over a longer period of time remain unknown.

However, Stewart does contend that an over-emphasis on low-fat diets has likely contributed to the obesity epidemic in the United States by encouraging an over-consumption of foods high in carbohydrates. He says high-carb foods are, in general, less filling, and people tend to get carried away with how much low-fat food they can eat. More than half of all American adults are estimated to be overweight, with a body mass index, or BMI, of 26 or higher; a third are considered to be obese, with a BMI of 30 or higher.

Stewart says the key to maintaining healthy blood vessels and vascular function seems ‒ in particular, when moderate exercise is included ‒ less about the type of diet and more about maintaining a healthy body weight without an excessive amount of body fat.

Among the researchers’ other key study findings, presented separately at the conference, was that consuming an extremely high-fat McDonald’s breakfast meal, consisting of two English muffin sandwiches, one with egg and another with sausage, along with hash browns and a decaffeinated beverage, had no immediate or short-term impact on vascular health.  Study participants’ blood vessels were actually less stiff when tested four hours after the meal, while endothelial or blood vessel lining function remained normal.

Researchers added the McDonald’s meal challenge immediately before the start of the six-month investigation to separate any immediate vascular effects from those to be observed in the longer study. They also wanted to see what happened when people ate a higher amount of fat in a single meal than recommended in national guidelines.

Previous research had suggested that such a meal was harmful, but its negative findings could not be confirmed in the Johns Hopkins’ analysis.  The same meal challenge will be repeated at the end of the study, when it is expected that its participants will still have lost considerable weight, despite having eaten more than the recommended amount of fat.

“Even consuming a high-fat meal now and then does not seem to cause any immediate harm to the blood vessels,” says Stewart.  However, he strongly cautions against eating too many such meals because of their high salt and caloric content.  He says this single meal ‒ at over 900 calories and 50 grams of fat ‒ is at least half the maximum daily fat intake recommended by the American Heart Association and nearly half the recommended average daily intake of about 2,000 calories for most adults.

All study participants were between the age of 30 and 65, and healthy, aside from being overweight or obese.  Researchers say that in the first study, because people were monitored for the period they lost the same amount of weight, any observed vascular differences would be due to what they ate.

Source: Johns Hopkins School of Medicine

Watch this video on Low-Carb, High-Fat Diet featuring Dr Mary Vernon.


Diabetes: Wake Up and Smell the Coffee ‒ Caffeine Harms Your Health

PREMATURE attributions of cause and effect should not be used to justify recommendations in favor of coffee drinking as beneficial to health, especially given the broad range of adverse effects attributable to caffeine.

Indeed, a growing body of research suggests that caffeine disrupts glucose metabolism and may contribute to the development and poor control of type 2 diabetes. A review article in the inaugural issue of Journal of Caffeine Research examines the latest evidence, contradicting earlier studies suggesting a protective effect of caffeine.

In the lengthy review that cites 49 past and current research studies, James Lane of Duke University describes numerous studies that have demonstrated caffeine’s potential for increasing insulin resistance (impaired glucose tolerance) in adults that do not have diabetes, an effect that could make susceptible individuals more likely to develop the disease.

In adults with type 2 diabetes mellitus (T2DM), studies have shown that the increase in blood glucose levels that occurs after they eat carbohydrates is exaggerated if they also consume a caffeinated beverage such as coffee. This effect could contribute to higher glucose levels in people with diabetes and could compromise treatment aimed at controlling their blood glucose.

More than 220 million people worldwide have diabetes and the links that have been revealed between diabetes and the consumption of caffeine beverages (especially coffee) are of monumental importance when it is acknowledged that more than 80% of the world’s population consumes caffeine daily.

Caffeine Effects on Insulin Resistance

The effects of caffeine on glucose metabolism have been studied in both healthy and T2DM individuals. The studies of healthy adults demonstrate the impact of caffeine when glucose regulation has not been compromised.

These results relate most directly to caffeine’s potential contributions to T2DM development, in those who are predisposed to the disease, and prevention. Studies of patients who have T2DM provide evidence of the potential clinical impact of caffeine on glucose management. Studies in both groups provide strong evidence that caffeine impairs glucose homeostasis through a transient increase in insulin resistance.

At least 17 studies were published between 1968 and 2010 describing the effects of caffeine on glucose metabolism in healthy nondiabetic adults. Most of the studies examined glucose and insulin responses to carbohydrate challenge.

Glucose and insulin levels were measured first under fasting conditions and then repeatedly for several hours after administration of a standard dose of glucose or carbohydrate administered orally or by intravenous infusion (IV).

Of the 14 studies that used this challenge protocol, all but one found evidence of insulin resistance after caffeine administration, compared to placebo control. Insulin responses were significantly larger after caffeine, indicating that more insulin was required to dispose of the glucose.

Even though more insulin was secreted after caffeine, none of the studies observed smaller glucose responses. Indeed, some found that caffeine potentiated the postchallenge glucose responses as well. Those who calculated whole-body insulin sensitivity index (ISI) found that caffeine decreased this measure of insulin sensitivity.

Three other studies used a technique known as the hyperinsulinemic-euglycemic clamp to measure caffeine’s effects on insulin sensitivity more directly. All three studies found that a moderate dose of caffeine significantly decreased glucose disposal compared to placebo control.

These results provide specific evidence that caffeine produces an acute reduction in insulin sensitivity (increased insulin resistance) in healthy nondiabetic men and women.

Studies have investigated the impact of caffeine on glucose tolerance in patients who have T2DM. Because diabetic patients typically have smaller insulin reserves, ingestion of carbohydrate usually produces a sustained hyperglycemia.

The effects of caffeine on this postprandial hyperglycemic response was first studied in 1967, when the observation was made that two cups of instant coffee (compared to hot water) exaggerated the rise in blood glucose that followed the IV injection of glucose solution.

This effect has been replicated in three more recent studies that tested the effects of double-blind administration of moderate doses of caffeine vs. placebo on glucose and insulin responses to carbohydrate challenge. The effects of caffeine were also studied in women who had gestational diabetes, a form of glucose dysregulation that can occur during pregnancy.

In all four studies, caffeine exaggerated the glucose and insulin responses to the carbohydrate challenge and decreased whole-body insulin sensitivity. These results confirm that caffeine increases insulin resistance in T2DM patients, as it does in nondiabetic patients. However, in T2DM patients, this effect also exaggerates the hyperglycemic response to carbohydrate.

Caffeine can impair glucose regulation in the real world as well as in the laboratory. An ambulatory study monitored glucose levels continuously for several days during the ordinary activities of a small group of T2DM coffee drinkers. The results provide evidence that caffeine impairs glucose regulation in the natural environment where caffeine is consumed, as it does in the laboratory.


In general, caffeine is thought to produce its widespread physiological effects through actions as a potent antagonist for adenosine receptors both centrally and peripherally. One hypothesis is that caffeine impairs glucose metabolism through the release of stress hormones, especially epinephrine and cortisol. Evidence from two human studies supports this hypothesis.

One study found that the drug propranolol, used to block the beta-adrenergic actions of epinephrine, abolished caffeine’s exaggeration of the postprandial insulin response and the reduction of whole-body insulin sensitivity.

A second study found that caffeine had no effects on glucose tolerance in a group of adults with tetraplegia, who did not produce increased epinephrine in response to caffeine. Both studies suggest that epinephrine could mediate caffeine’s effects on glucose and insulin resistance.

However, a study that directly compared caffeine with high- and low-dose epinephrine infusions for their effects on insulin sensitivity found that caffeine did not raise epinephrine levels high enough to fully account for effects on glucose metabolism.

Although evidence is strong that caffeine produces a transient resistance to insulin action and impairment of glucose tolerance, doubts have been raised about the relevance of these acute effects to the potential public health impact of chronic daily consumption of caffeinated beverages like coffee, tea, and soft drinks.

Perhaps the strongest doubt arises from the common belief that habitual consumption of coffee or other caffeinated beverages leads to the development of tolerance to caffeine and the disappearance of acute effects after daily use. However, there is good reason to believe that habitual caffeine intake does not eliminate the increases in insulin resistance.

A second doubt concerns whether drinking coffee has the same effects as caffeine ingested in capsules. This question is especially relevant given the evidence that heavy coffee drinking is associated with lower risk of developing T2DM. Evidence from studies suggests that coffee has effects similar to pure caffeine. Consumption of coffee, tea, and caffeinated soft drinks may all have similar effects, due to the caffeine that each contains.

A third doubt about the public health relevance of these effects is whether the effects of caffeine on glucose metabolism are sufficiently large to be of clinical importance for the prevention or management of T2DM. Evidence suggests that the effects of habitual caffeine consumption could be large enough to offset at least part of the therapeutic effects of medications commonly prescribed for the management of glucose in T2DM. In addition, caffeine abstinence, as a lifestyle intervention, might yield improvements in chronic glucose control large enough to qualify as a useful adjunctive treatment.

Contradictory Evidence

Although the experimental results clearly indicate that caffeine consumption should be a public health concern for the prevention and management of T2DM, epidemiological studies have reported results that contradict this conclusion. These studies have consistently found that nondiabetic adults who are heavy coffee drinkers, typically four to six cups per day or more, have a lower risk of developing T2DM in subsequent years.

Causal explanations require a plausible mechanism, which has not been established so far for the link between heavy coffee consumption and protection from T2DM. The most common speculation is that one or more of the many compounds in coffee, other than caffeine, is responsible.

This idea is supported by evidence linking decaffeinated coffee consumption to a lower risk of T2DM in some studies. However, research into the effects of these coffee compounds in humans is in its very early stages. It would be premature to assume that these compounds are bioactive and protect against the pathological processes that lead to T2DM.

An alternative interpretation of the epidemiological evidence is that heavy coffee drinking is not the true cause of lower risk, but is simply a marker for another factor that is responsible. After all, individuals select for themselves how much coffee they will consume, and consumption of six of more cups is relatively rare

However, recent research does suggest another possibility that could explain the inverse association of coffee and T2DM risk. Consumption of sugar-sweetened beverages, such as soft drinks, fruit drinks, iced tea, and energy drinks, has recently been associated with an increased risk of T2DM.

A meta-analysis of the studies reporting this association suggests that those individuals who drink one to two servings per day have a 26% greater risk of developing T2DM than those who drink none, or less than 1 per month.

Common sense suggests that those individuals who are heavy coffee drinkers probably consume little or none of these other beverages. The apparent benefits of coffee drinking may simply be due to an avoidance of the sugar-sweetened alternatives.

The epidemiological studies have provided new directions for investigation, such as the biological activity of noncaffeine compounds found in coffee. Beyond the potential to discover new chemical compounds, however, their results probably offer little benefit to diabetes prevention and public health.

Premature attributions of cause and effect should certainly not be used to justify recommendations in favor of coffee drinking as beneficial to health, especially given the broad range of adverse effects attributable to caffeine.

Study To Check If Garlic And Asparagus Can Fight Diabetes

Researchers are investigating whether foods including garlic and asparagus could help weight loss and diabetes. In news that could make ardent vegans and vegetarians feel a little smug, the charity Diabetes UK is examining whether foods rich in fibre could supress people’s appetites and reduce their blood sugar levels.

Fermentable carbohydrates, a kind of fibre, are found in foods such as asparagus, garlic, chicory and Jerusalem artichokes. If the foods are found to have this effect it could revolutionise treatments to tackle obesity and type 2 diabetes. Recent research has suggested that foods high in fermentable carbohydrates are particularly good at stabilising blood sugar levels.

The three-year study by the Nutrition and Research Group at Imperial College London, aims to establish whether these carbohydrates cause the release of gut hormones that could reduce appetite and enhance insulin sensitivity, which could reduce blood sugar levels and help control weight. The carbohydrates will be given to participants in the study as a daily supplement.

Dietitian Nicola Guess, who is leading the study, said: “By investigating how appetite and blood glucose levels are regulated in people at high risk of type 2 diabetes, it is hoped that we can find a way to prevent its onset. Type 2 diabetes accounts for 90% of diabetes cases and, if left untreated, can lead to serious health complications including heart disease, stroke, blindness, kidney failure and amputation, according to Diabetes UK.

Dr Iain Frame, the charity’s director of research, said: “It is unlikely that any single measure used on its own will bring about improved prevention of type 2 diabetes. But it’s hoped that the research being funded at Imperial College will help by aiming to develop an easy and affordable way to help people to reduce their risk of developing type 2 diabetes and managing their blood glucose levels.”

Thank you David Batty/Guardian

The Glycemic Index (Part 1)

The glycemic index ranks foods on how they affect our blood sugar levels. This index measures how much your blood sugar increases after you eat.

When you make use of the glycemic index to prepare healthy meals, it helps to keep your blood sugar levels under control. This is especially important for people with diabetes, although athletes and people who are overweight also stand to benefit from knowing about this relatively new concept in good nutrition.

Studies of large numbers of people with diabetes show that those who keep their blood sugar under tight control best avoid the complications that this disease can lead to. The experts agree that what works best for people with diabetes — and probably everyone — is regular exercise, little saturated and trans fat, and a high-fiber diet. That is excellent advice — as far as it goes.

The real problem is carbohydrates, and that’s what the glycemic index is all about. Foods high in fat or protein don’t cause your blood sugar level to rise much.

The official consensus remains that a high-carbohydrate diet is best for people with diabetes. However, some experts recommend a low-carbohydrate diet, because carbohydrates break down quickly during digestion and can raise blood sugar to dangerous levels. A low-glycemic diet avoids both extremes.

Many carbohydrate-rich foods have high glycemic indexes, and certainly are not good in any substantial quantity for people with diabetes. Other carbohydrates break down more slowly, releasing glucose gradually into our blood streams and are said to have lower glycemic indexes.

The really shocking results of G.I. studies are in which foods produce the highest glycemic response. They include many of the starchy foods we eat a lot of, including most bread, most breakfast cereals, and baked potatoes. But table sugar — long believed to be the worst thing for people with diabetes — isn’t as high on the index.

Low glycemic foods include beans, barley, pasta, oats, and some types of rice. Acidic fruits have low glycemic indexes. Likewise, vinegar and lemon juice — as in salad dressing — help reduce the glycemic load.

A lot of people still think that it is plain table sugar that people with diabetes need to avoid. The experts used to say that, but the glycemic index shows that starchy complex carbohydrates, like baked potatoes, can be even worse.

Before the development of the glycemic index beginning in 1981, scientists assumed that our bodies absorbed and digested simple sugars quickly, producing rapid increases in our blood sugar level. This was the basis of the advice to avoid sugar, a proscription recently relaxed by the American Diabetes Association and others.

Many of the glycemic index results have been surprises. For example, baked potatoes have a glycemic index considerably higher than that of table sugar.

A more pleasant surprise is the very low glycemic index of a tasty bean called chana dal. Another pleasant surprise is pearled barley, which has the lowest glycemic index of any grain.

Other Important Diet Considerations
The glycemic index should not be your only criterion when selecting what to eat. The total amount of carbohydrate, the amount and type of fat, and the fiber and salt content are also important dietary considerations. The glycemic index is most useful when deciding which high-carbohydrate foods to eat.

But don’t let the glycemic index lull you into eating more carbohydrates than your body can handle. The number of grams of carbohydrate we consume is awfully important. Make sure you know the carbohydrate content of the foods you eat by studying the nutritional information on the package.

Factors such as variety, cooking, and processing may effect a food’s GI. Foods particularly sensitive to these factors include bananas, rice, and potatoes.

In addition, the glucose response to a particular food may be somewhat individual. So it is probably a good idea to carefully watch your own blood sugar after eating foods you have questions about and determine if they have high or low GI for you. If you find a specific food produces an unexpected result, either high or low, take note of it and incorporate that into your meal planning.

Also note that the numbers vary from study to study. This may be due to variations in the individuals in a particular study, other foods consumed at the same time, or different methods of preparation, since your body can absorb some foods better when they are well cooked.

Free Foods
Most of the foods tested are high in carbohydrates. Some may wonder at the gaps — why other high-carbohydrate low-calorie foods like celery (or tomatoes or similar foods) have never been tested. The problem is a technical one for the testers, because they would be so hard put to get anyone to volunteer to eat 50 grams of carbohydrate from celery — it’s just too much celery to think about! Essentially, from a glycemic index standpoint, celery and foods like it can be considered as free foods.

Mixed Meals
Some people wonder if the glycemic index can predict the effect of a mix meal containing foods with very different indexes. Studies have shown that it does that job very well, too.

You can quite readily predict the glycemic index of a mixed meal. Simply multiply the percent of total carbohydrate of each of the foods by its glycemic index and add up the results to get the glycemic index of the meal as a whole.

750 Foods
At the time of this writing, scientists have so far measured the glycemic indexes of about 750 high-carbohydrate foods (they are continually testing new foods). The key is to eat little of those foods with a high glycemic index and more of those foods with a low index.

Thank you David Mendosa

Diabetes Diet Cuts Heart Attack Risk in Half

Thе’re no harm in repeating this ad nauseum that even though incidence οf diabetes hаѕ doubled over thе past 10 years, many people remain unaware thаt thеу hаνе become victim tο thіѕ ѕіlеnt killer disease. Millions οf people аrе pre-diabetic, indicating a failing metabolism that wіll lead tο full diabetes, typically іn 6 months tο 2 years time.

Surprisingly, thе diagnosis οf diabetes doesn’t hаνе thе same impact οn patients аѕ οthеr potentially lethal diseases, due tο thе subtle manifestation οf symptoms before thе disease progresses fully. Bесаυѕе οf thіѕ, people аrе less lіkеlу tο take diabetes seriously, placing thеm аt high risk fοr heart disease аnd a host οf debilitating diabetic complications.

Diabetes Doubles thе Risk οf Heart Attack аnd Stroke
I will never tire of pointing out that innumerable studies have found thаt diabetes doubles thе risk οf developing life-threatening events such аѕ a heart attack οr stroke. Type II diabetes іѕ largely a disease caused bу poor lifestyle choices аnd іѕ perpetuated bу a diet οf processed junk foods that leads tο complete metabolic dysfunction.

But the good news is that diabetes саn bе controlled bу following a strict meal рlаn that drastically limits high carbohydrate foods аnd sugary drinks. Many people hаνе bееn аblе tο minimize аnd resolve blood sugar surges аnd neuropathic complications bу eliminating specific foods that сrеаtе metabolic imbalance, аnd сυt thеіr risk οf a heart attack іn half.

Carbs Count, Sο Count Thеm
Thе mοѕt іmрοrtаnt thing tο understand whеn working tο prevent οr treat type II diabetes іѕ thаt a low-fаt, high-carb diet іѕ based οn аn ancient understanding οf thе disease аnd wіll promote disease progression. Thе οnlу way tο take charge οf diabetes іѕ tο track аnd monitor еνеrу morsel οf food уου eat, аnd keep track οf thе carbohydrate count.

Carbs, regardless οf thе dietary source, cause blood sugar tο rise аnd insulin resistance tο develop. Once thіѕ metabolic imbalance bеgіnѕ, thе οnlу way tο keep іt οn track іѕ tο severely limit carbohydrate intake. Fats аnd protein hаνе a limited effect οn blood sugar аnd actually hеlр tο flatten blood sugar spikes.

Target Less Thаn 100 Grams οf Carbohydrates Each Day
Many people eat more thаn 100 grams οf carbohydrates each meal, causing wild swings іn post meal blood sugars whісh hаνе bееn shown tο lead tο metabolic dysfunction, diabetes аnd serious complications. Limit carbs frοm аll sources, including vegetables, tο nο more thаn 30 grams each meal. (Yου’ll need tο υѕе nutritional tracking software tο calculate carb counts.)

Weigh аnd measure everything аnd record іt before уου eat. Bе ассυrаtе, аѕ small deviations саn сrеаtе bіg blood sugar swings. Yου’ll find thаt tο hit уουr target carbs fοr each meal, thеrе’s nο room fοr junk foods, breads, pasta, sugared drinks, аnd even salad dressing whісh аrе pumped full οf sugar.

Mаkе fresh vegetables thе core οf each meal аnd compliment wіth solid protein аnd fаt sources frοm meats, nuts, seeds аnd legumes.

Check Blood Sugar Aftеr Each Meal
Thе οnlу trυе way tο know іf уου саn tolerate more carbs іѕ tο test уουr blood sugar wіth аn inexpensive meter. Check уουr reading 1 аnd 2 hours аftеr eating, аѕ thіѕ іѕ whеn thе highest blood sugar readings wіll bе recorded. Mаkе sure thаt уουr 1 hour reading іѕ nο higher thаn 140 mg/dl, аnd thе 2 hour reading іѕ below 120 mg/dl.

Readings above thеѕе levels indicate metabolic instability, аnd thе need tο lower уουr carbohydrate intake. Blood sugar readings above 140 mg/dl аrе associated a doubling οf risk οf heart attack аnd dаngеrουѕ complications frοm kidney disease, blindness аnd nerve dаmаgе.

Monitor уουr blood sugar аftеr еνеrу meal, аnd soon уου’ll know exactly whісh foods cause thе lаrgеѕt swings аnd mυѕt bе avoided.

Diabetes cases wіll continue tο double еνеrу decade, jeopardizing thе lives οf millions, unless people аrе educated tο take control οf thеіr diet. Thе disease іѕ іn уουr control, аnd οnlу уου саn determine hοw іt progresses.

Many people hаνе shown thаt thеу саn prevent аnd even treat diabetes bу incorporating аn ultra-low carb diet аnd monitoring blood sugar levels carefully аftеr meals. Cυt уουr risk οf a heart attack аnd diabetic complications bу taking charge οf уουr diet аnd lifestyle.

Thank you Barry Lee

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