Elevated cholesterol levels
Archived from the original on 13 October Retrieved 18 December Just how much of an effect exercise has on cholesterol is also a matter of debate. A meta-analysis of individual data for one million adults in 61 prospective studies". The DASH study used a rigorous design called a randomized controlled trial RCT , and it involved teams of physicians, nurses, nutritionists, statisticians, and research coordinators working in a cooperative venture in which participants were selected and studied in each of these five research facilities.
Dangers of Fasting for Weight Loss
Fasts lasting a day or two are unlikely to be dangerous for most healthy adults. But high-risk people, the elderly, anyone with a chronic disease, pregnant women, and children are advised against any type of fasting.
The real danger lies in staying on the fast for prolonged periods, anywhere from three days to a month. When you dramatically reduce your calorie intake, you will lose weight. But it can also cause all kinds of health problems, including muscle loss. Further, when you start fasting, your body goes into conservation mode, burning calories more slowly.
Keep in mind that the initial weight lost on a fast is primarily fluid or "water weight," not fat. And when you go back to eating, any lost weight usually gets a return ticket back.
Not only do most people regain weight lost on a fast, they tend to add a few extra pounds because a slower metabolism makes it easier to gain weight. Worse, the weight that is regained is likely to be all fat -- lost muscle has to be added back at the gym. Side effects of fasting include dizziness , headaches , low blood sugar , muscle aches, weakness , and fatigue. Two DASH trials were designed and carried out as multi-center, randomized, outpatient feeding studies with the purpose of testing the effects of dietary patterns on blood pressure.
The standardized multi-center protocol is an approach used in many large-scale multi-center studies funded by the NHLBI. A unique feature of the DASH diet was that the foods and menu were chosen based on conventionally consumed food items so it could be more easily adopted by the general public if results were positive. The nutritional conceptualization of the DASH meal plans was based in part on this research.
Two experimental diets were selected for the DASH study and compared with each other, and with a third: Magnesium and Potassium levels were close to the 75th percentile of U. The DASH diet was designed to provide liberal amounts of key nutrients thought to play a part in lowering blood pressure, based on past epidemiologic studies. One of the unique features of the DASH study was that dietary patterns rather than single nutrients were being tested.
Researchers have also found that the DASH diet is more effective than a low oxalate diet in the prevention and treatment of kidney stones, specifically calcium oxalate kidney stones the most common type. Participants ate one of the three aforementioned dietary patterns in 3 separate phases of the trial, including 1 Screening, 2 , Run-in and 3 Intervention. In the screening phase, participants were screened for eligibility based on the combined results of blood pressure readings.
In the 3 week run-in phase, each subject was given the control diet for 3 weeks, had their blood pressure measurements taken on each of five separate days, gave one hour urine sample and completed a questionnaire on symptoms. At this point, subjects who were compliant with the feeding program during the screening phase were each randomly assigned to one of the three diets outlined above, to begin at the start of the 4th week.
The intervention phase followed next; this was an 8-week period in which the subjects were provided the diet to which they had been randomly assigned. The first group of study subjects began the run-in phase of the trial in September while the fifth and final group began in January Alcohol was limited to no more than two beverages per day, and caffeine intake was limited to no more than three caffeinated beverages.
The minority portion of the study sample and the hypertensive portion both showed the largest reductions in blood pressure from the combination diet against the control diet. The hypertensive subjects experienced a drop of At the end of the intervention phase, Apart from only one subject on the control diet who was suffering from cholecystitis, other gastrointestinal symptoms had a low rate of incidence.
Like the previous study, it was based on a large sample participants and was a multi-center, randomized, outpatient feeding study where the subjects were given all their food. The day intervention phase followed, in which subjects ate their assigned diets at each of the aforementioned sodium levels high, intermediate and low in random order, in a crossover design.
The primary outcome of the DASH-Sodium study was systolic blood pressure at the end of the day dietary intervention periods. Excess calories from carbohydrates are not any more fattening than calories from other sources.
As of [update] the AHA stated categorically that it doesn't recommend high-protein diets. Some of these diets restrict healthful foods that provide essential nutrients and don't provide the variety of foods needed to adequately meet nutritional needs.
People who stay on these diets very long may not get enough vitamins and minerals and face other potential health risks. Eckel , past president, noted that a low-carbohydrate diet could potentially meet AHA guidelines if it conformed to the AHA guidelines for low fat content.
The position statement by the Heart Foundation regarding low-carbohydrate diets states: Low-carbohydrate diets became a major weight loss and health maintenance trend during the late s and early s.
Because of the substantial controversy regarding low-carbohydrate diets, and even disagreements in interpreting the results of specific studies, it is difficult to objectively summarize the research in a way that reflects scientific consensus.
Although there has been some research done throughout the twentieth century, most directly relevant scientific studies have occurred in the s and early s and, as such, are relatively new and the results are still debated in the medical community. A systematic review studying the effects of a low-carbohydrate diet LCD on weight loss and cardiovascular risk factors showed that the diet that was studied was associated with significant decreases in body weight, body mass index , abdominal circumference, blood pressure , triglycerides , fasting blood sugar , blood insulin and plasma C-reactive protein , as well as an increase in high-density lipoprotein cholesterol HDL.
Low-density lipoprotein cholesterol LDL and creatinine did not change significantly. The study found the LCD was shown to have favorable effects on body weight and major cardiovascular risk factors but concluded the effects on long-term health are unknown. The study did not compare health benefits of LCD to low-fat diets. A meta-analysis published in the American Journal of Clinical Nutrition in compared low-carbohydrate, Mediterranean, vegan, vegetarian, low-glycemic index, high-fiber, and high-protein diets with control diets.
The researchers concluded that low-carbohydrate, Mediterranean, low-glycemic index, and high-protein diets are effective in improving markers of risk for cardiovascular disease and diabetes.
Advocates of low-carbohydrate diets generally dispute any suggestion that such diets cause weakness or exhaustion except in the first few weeks as the body adjusts , and indeed most highly recommend exercise as part of a healthy lifestyle. Some critics imply or explicitly argue that vegetables and fruits are inherently all heavily concentrated sources of carbohydrates so much so that some sources treat the words 'vegetable' and 'carbohydrate' as synonymous.
Thus, in absolute terms, even sweet fruits and berries do not represent a significant source of carbohydrates in their natural form, and also typically contain a good deal of fiber which attenuates the absorption of sugar in the gut. Most vegetables are low- or moderate-carbohydrate foods in the context of these diets, fiber is excluded because it is not a nutritive carbohydrate. Some vegetables, such as potatoes , have high concentrations of starch, as do maize and rice. Most low-carbohydrate diet plans accommodate vegetables such as broccoli , spinach , cauliflower , and peppers.
Nevertheless, debate remains as to whether restricting even just high-carbohydrate fruits, vegetables, and grains is truly healthy. Contrary to the recommendations of most low-carbohydrate diet guides, some individuals may choose to avoid vegetables altogether to minimize carbohydrate intake.
Low-carbohydrate vegetarianism is also practiced. Raw fruits and vegetables are packed with an array of other protective chemicals, such as vitamins, flavonoids , and sugar alcohols. Some of those molecules help safeguard against the over-absorption of sugars in the human digestive system. Some evidence indicates the increasingly large percentage of calories consumed as refined carbohydrates is positively correlated with the increased incidence of metabolic disorders such as type 2 diabetes.
Some evidence indicates the human brain — the largest consumer of glucose in the body — can operate more efficiently on ketone bodies. In , the Canadian government ruled that foods sold in Canada could not be marketed with reduced or eliminated carbohydrate content as a selling point, because reduced carbohydrate content was not determined to be a health benefit. The government ruled that existing "low carb" and "no carb" packaging would have to be phased out by In , John Rollo reported on the results of treating two diabetic Army officers with a low-carbohydrate diet and medications.
A very low-carbohydrate, ketogenic diet was the standard treatment for diabetes throughout the nineteenth century. In , William Banting , a formerly obese English undertaker and coffin maker, published "Letter on Corpulence Addressed to the Public", in which he described a diet for weight control giving up bread , butter , milk , sugar , beer , and potatoes. In the early s Frederick Madison Allen developed a highly restrictive short term regime which was described by Walter R.
The process was halted if sugar appeared in the person's urine. In , Richard Mackarness M. Mackarness also challenged the "calorie theory" and referenced primitive diets such as the Inuit as examples of healthy diets with a low-carbohydrate and high-fat composition. The "Stillman diet" is a high-protein , low-carbohydrate, and low-fat diet. It is regarded as one of the first low-carbohydrate diets to become popular in the United States. In , Robert Atkins published Dr.
Atkins Diet Revolution , which advocated the low-carbohydrate diet he had successfully used in treating patients in the s having developed the diet from a article published in JAMA. The concept of the glycemic index was developed in by David Jenkins to account for variances in speed of digestion of different types of carbohydrates. In the s, Atkins published an update from his book, Dr. Atkins New Diet Revolution , and other doctors began to publish books based on the same principles.
This has been said to be the beginning of what the mass media call the "low carb craze" in the United States. In the United States, the diet has continued to garner attention in the medical and nutritional science communities, and also has inspired a number of hybrid diets that include traditional calorie-counting and exercise regimens.
From Wikipedia, the free encyclopedia. This is the latest accepted revision , reviewed on 12 September Not to be confused with slow carb diet. This article is about low-carbohydrate diets as a lifestyle choice or for weight loss. For low-carbohydrate dietary therapy for epilepsy, see Ketogenic diet. This article has multiple issues.
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