High-Protein Low-Carb Diets and Type 2 Diabetes Management

Introduction

Diseases like diabetes depend heavily on a patient's nutritional intake for effective management. Patients have traditionally been advised to reduce direct sugar consumption, since the disease renders the body incapable of regulating free sugar levels in the bloodstream. Because direct sugars must be avoided, many dieticians have recommended a dietary pattern lower in carbohydrates and richer in proteins, vitamins, and fiber — foods that promote satiety while simultaneously reducing carbohydrate intake. However, recent studies have accused high-protein, low-carbohydrate diets of either aggravating diabetic patients' conditions or causing secondary medical complications. This paper examines that debate in greater detail.

Understanding Type 2 Diabetes

Diabetes mellitus is one of the most common diseases worldwide, particularly among people past middle age, though the disease is increasingly observed in young children and adolescents as well. Even in younger patients, the disease often arises from sedentary habits and genetic predisposition. In the United States, diabetes is a significant contributor to mortality. Beyond its direct effects, diabetes can also act as a precursor to many other conditions, potentially leading to the failure of vital organs such as the kidneys, eyes, and liver (Author not known 1, 2002).

Depending on the amount of insulin produced in the body, diabetes is divided into two main classes. Type 1 diabetes occurs when the patient's body produces no insulin at all. In Type 2 diabetes, by contrast, the patient does produce insulin, but either at levels far below what the body requires or in a form the body cannot use efficiently. Type 2 diabetes is by far the most common variant, accounting for approximately 90% of all diabetes cases.

Beyond the well-known effect of elevated blood sugar, Type 2 diabetes causes serious physiological changes in the body. Scientists believe the disease typically progresses through three common pathways:

1. At the onset of the disease, patients who adopt sedentary habits first achieve caloric balance and then a caloric surplus, leaving the body with more energy than it requires. This excess carbohydrate is converted to fat, and the patient becomes obese.

2. Fat stored in the muscles generates hormonal signals that cause insulin resistance.

3. Insulin production — which may be further impaired by certain medications — becomes so severely compromised that vital organs such as the kidneys and liver are ultimately affected.

Scientists have found that the lower the amount of body fat, the lower the resistance to insulin. Therefore, the best approach to countering the effects of Type 2 diabetes is to reduce body fat.

As one research summary explains: "Prevention of type 2 diabetes requires arrest of the progressive beta-cell dysfunction and stabilization of glucose concentrations at non-diabetic levels. Anything short of this arrest and stabilization will only delay the onset of type 2 diabetes. Theoretically, type 2 diabetes could be prevented or delayed by three types of interventions: 1) interventions that limit fat accumulation in the body (less obesity = less insulin resistance); 2) interventions that uncouple obesity from insulin resistance (less insulin resistance = less beta-cell failure); and 3) interventions that directly preserve beta-cell mass and/or function, despite the high secretory demands imposed by insulin resistance (better beta-cell function = less diabetes)" (Author not known 2, 2003).

The treatment of Type 2 diabetes does not follow a single approach for all patients, as doctors may administer different treatments depending on individual circumstances. Although there is substantial ongoing research into the role of diet in controlling Type 2 diabetes, the results are often conflicting. For instance, micronutrient levels were found not to affect, or be affected by, Type 2 diabetes in most populations studied — though researchers acknowledge this remains a grey area requiring further investigation (Osei, 2001). Conversely, a high fat content in the diet, particularly saturated fats, has been linked to impaired insulin action in the body (Author not known 3, 2002).

The term Syndrome X is used to describe a cluster of disease-causing conditions and symptoms — including high blood pressure, high triglycerides, decreased HDL cholesterol, and obesity — that tend to appear together in some individuals and increase their risk of both diabetes and heart disease. The term can also refer to insulin resistance itself, which causes an increase in blood triglyceride levels.

Low-Carbohydrate and High-Protein Diet Research

The extensive body of literature linking dietary fat to increased insulin resistance has prompted scientists to investigate foods that are low in carbohydrates and high in proteins as a means of controlling the harmful effects of Type 2 diabetes. This approach is based on the fact that the body's metabolic pathways convert excess sugars into fat. It is theorized that by keeping carbohydrate content lower, the modern diabetic diet would not contribute to elevated blood sugar levels. A great deal of research has been conducted to demonstrate that a low-carbohydrate diet is more beneficial than a low-fat diet for diabetes management.

Much of this research has centered on the Atkins diet, and the popularity of that diet helped give rise to two significant schools of thought regarding diabetes management. Supporters of the Atkins diet argued that reducing carbohydrates is both necessary and medically safe, while opponents maintained that drastic carbohydrate reduction would cause serious health problems. Beyond the commercial interests surrounding the product, the research outcomes from studies on the Atkins diet are of direct relevance to this analysis.

The high-fat, low-carbohydrate Atkins diet was long dismissed by medical establishments as a hazard to cardiac health, owing to presumed adverse effects on cholesterol, blood pressure, triglyceride levels, and cardiovascular inflammation. However, more recent experimental observations have presented a different picture. Studies indicate that rather than worsening these markers, the Atkins diet actually improved cholesterol, blood pressure, triglycerides, and inflammatory markers compared with standard diets. Participants lost approximately twice as much weight in a few months as those following the conventional low-fat, high-carbohydrate diet recommended by most health professionals — and they did so without incurring additional cardiovascular risk. Although the supporting studies were relatively short and small in scale, the consistency of results attracted the attention of even mainstream medical professionals who had previously dismissed the dietary approach.

Other researchers have documented that low-carbohydrate dieting increases weight loss without creating risky cardiovascular side effects in obese adolescents (Sondike, Copperman, and Jacobson, 2000). The Atkins diet caused people to lose more weight even when they were consuming more total calories than participants on a conventional healthy diet. Until recently, the medical community held a largely unanimous view that any diet emphasizing meat, eggs, and cheese while discouraging bread, rice, and fruit was both absurd and dangerous. The American Medical Association had in 1972 dismissed the diet as "potentially dangerous," noting that approximately two-thirds of its calories would come from fat — more than double the recommendation for healthy eating. Carbohydrates were considered essential to a good diet, and fat was seen as perilous. Conventional scientists rejected the contention by Atkins proponents that saturated fat is harmful only when consumed alongside large amounts of carbohydrates.

Despite the medical establishment's skepticism, the Atkins diet achieved wide acceptance among obese individuals, and reports from around the world contradicted the medical community's concerns. University-based research also suggested that cardiovascular risk factors tended to improve rather than worsen on the diet.

The North American Association for the Study of Obesity undertook a study that was, in large part, intended to disprove the Atkins approach. However, the study's leader, Foster, reported that after three months, overweight men and women on the Atkins diet lost an average of 8.55 kilograms and 4.5 kilograms more, respectively, than participants following the standard high-carbohydrate approach. Notably, Atkins dieters also saw improvements in cholesterol: while their LDL ("bad") cholesterol rose by seven points, their HDL ("good") cholesterol increased by almost 12 points. Among the high-carbohydrate dieters, bad cholesterol declined slightly but good cholesterol remained unchanged. Triglyceride levels among Atkins dieters fell by 22 points — a finding that has been extensively researched and confirmed elsewhere (Yancy, Bakst, Bryson, et al., 2001).

Two studies published in the New England Journal of Medicine provided additional evidence that the Atkins diet may be more effective for weight loss than low-fat, calorie-restricted diets and may produce more positive metabolic changes. In the first study, 64 obese subjects prone to overeating — either with diabetes or metabolic syndrome — were assigned to either a low-carbohydrate diet or a low-fat, calorie-restricted diet. While neither group achieved remarkable weight loss overall, those on the low-carbohydrate diet lost considerably more weight. The low-carbohydrate diet also produced lower triglyceride levels and a greater improvement in insulin sensitivity (Samaha et al., 2003). In the second study, 63 obese participants were randomly assigned to either the Atkins diet or a conventional low-calorie diet. Those on the Atkins diet lost appreciably more weight during the first six months, though by the end of one year the difference in weight loss between the two groups had narrowed. Nevertheless, patients on the Atkins diet showed a considerable increase in HDL cholesterol and a significant decrease in triglyceride levels throughout the entire study period (Foster et al., 2003).

Taken together, this research suggests that restriction of carbohydrates is more important than restriction of fat when managing diabetes. Low-carbohydrate foods are characterized by lower levels of both direct and indirect sugars, a higher proportion of dietary fiber that aids digestion and nutrient absorption, and a higher protein content that promotes satiety and reduces food cravings. Research further shows that restricting fat in the diet can trigger cravings and overeating, while restricting sugars reduces the body's surplus energy stores. When carbohydrates are consumed in excess, they are converted to fat in the body, which in turn reduces insulin sensitivity. As one researcher has noted, consumption of a high-carbohydrate diet by a person with Type 2 diabetes leads to elevated triglyceride levels, since excess carbohydrate that cannot be converted to fatty acids produces additional glucose, which is then stored as fat (Stein, 2000). When carbohydrates are reduced, the body draws on existing energy reserves — which is why combining a sound exercise regimen with a low-carbohydrate diet can produce significant benefits for diabetic patients.

Conclusion

An authoritative decision can be made only after adequate research examining various aspects of the issue, including the types of diabetic cases involved, the types of carbohydrates and their specific effects on the body, the consequences of sustained high protein intake, the role of increased dietary fat, and the differences in ethnicity that may predispose certain populations to the disease. Until such research is available, a moderate and individually tailored approach to carbohydrate restriction — guided by a qualified healthcare provider — appears to be the most evidence-based strategy for dietary management of Type 2 diabetes.

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