Low-carbohydrate diets may increase the risk of heart disease: scientific explanation
Low-carbohydrate diets have gained considerable popularity in recent years. Promoted as effective strategies for weight loss, improved blood sugar control, and appetite reduction, they have become widely adopted in many countries. However, some recent studies suggest that these diets, particularly when poorly balanced or followed long term, may be associated with an increased risk of cardiovascular disease. This hypothesis has sparked significant scientific debate and deserves careful examination.
Understanding low-carbohydrate diets
A low-carbohydrate diet involves significantly reducing the intake of sugars and starches while relatively increasing the consumption of fats and sometimes proteins. The strictest versions, such as the ketogenic diet, drastically limit carbohydrate intake to induce ketosis, a metabolic state in which the body primarily uses fat as its main energy source.
In the short term, these diets may lead to rapid weight loss, lower circulating insulin levels, and improvements in certain metabolic markers. However, their long-term effects on cardiovascular health largely depend on the quality of the nutrients used to replace carbohydrates.
The role of fats in cardiovascular risk
When carbohydrates are reduced, they are often replaced with fats. If these fats mainly come from saturated sources such as processed meats, high-fat dairy products, or certain industrial oils, this may lead to increased levels of LDL cholesterol, a major risk factor for cardiovascular disease.
Elevated LDL cholesterol promotes the accumulation of plaque within the arteries, a process known as atherosclerosis. Over time, this buildup can result in serious events such as heart attacks or strokes.
In contrast, if fats are primarily unsaturated and derived from sources such as olive oil, nuts, seeds, and fatty fish, the impact on lipid profiles may be more favorable. Therefore, the type of fat consumed plays a crucial role in determining cardiovascular risk.
Impact on fiber intake and vascular health
Reducing carbohydrates may also lead to decreased intake of dietary fiber, particularly if fruits, legumes, and whole grains are significantly restricted. Fiber plays an essential role in cholesterol regulation, blood sugar stabilization, and protection against vascular inflammation.
Insufficient fiber intake can also disrupt the gut microbiota, which is increasingly recognized as a key factor in cardiovascular health. An imbalanced microbiome may promote systemic inflammation and indirectly contribute to the development of heart disease.
Scientific evidence and interpretation
Some large observational studies have reported an association between very low-carbohydrate diets and an increased risk of cardiovascular events, especially when protein and fat sources are predominantly animal-based and processed.
However, it is important to note that such studies do not necessarily establish a direct cause-and-effect relationship. Overall dietary patterns, lifestyle habits, physical activity levels, and other variables also influence outcomes. Moreover, well-designed low-carbohydrate diets rich in vegetables, unsaturated fats, and high-quality protein sources may not carry the same level of risk.
Toward a balanced nutritional approach
Rather than framing macronutrients as opposing forces, many experts advocate for a quality-focused dietary approach. Reducing refined carbohydrates and added sugars is widely considered beneficial. However, excessive exclusion of complex carbohydrate sources and fiber-rich foods may be counterproductive.
A balanced diet that emphasizes complex carbohydrates, unsaturated fats, and diverse protein sources appears to provide better long-term cardiovascular protection. Personalizing dietary strategies according to metabolic profiles and medical history remains essential.
In conclusion, low-carbohydrate diets may increase the risk of cardiovascular disease when they are high in saturated fats and low in fiber. Nevertheless, the overall risk depends primarily on dietary quality. A moderate, diverse, and scientifically guided approach remains the most prudent strategy for preserving heart health.
