Insulin resistance is a common metabolic disruption that can increase the risk of type 2 diabetes, cardiovascular disease, metabolic syndrome, and obesity. It occurs when the body's cells fail to respond appropriately to insulin, causing increased insulin levels and chronically high blood insulin levels.Β
As insulin resistance becomes increasingly common, there is growing interest in how diet changes can treat insulin resistance. Several dietary approaches are widely studied, including high-protein diets, low-carbohydrate diets, the Mediterranean diet, intermittent fasting, and time-restricted feeding.Β
This article discusses the effects of a high-protein diet on treating insulin resistance.
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What Is Insulin Resistance?
Insulin is a hormone released by the beta cells of the pancreas in response to an elevation in blood glucose. When carbohydrates are metabolized, blood glucose rises, which signals the body to release insulin.Β
Insulin functions in two ways:
- Lowers blood glucose
- Serves as a signaling molecule for different cells
Insulin resistance is the metabolic disruption that occurs when cells fail to respond to insulin. In turn, the pancreas releases more insulin to overcome this blunted response.
Eventually, blood glucose remains consistently elevated, which results in insulin resistance, prediabetes, and then type 2 diabetes mellitus. A chronically elevated insulin level perpetuates inflammation, which worsens chronic disease progression.Β
Causes of Insulin Resistance
Several factors can contribute to the development of insulin resistance:
- Proinflammatory diet
- Sedentary lifestyle
- Chronic stress
- Inadequate sleep
- Genetic predispositions
- Hormonal imbalances
What Is A High-Protein Diet?
A high-protein diet usually includes 30-40% of calories from protein, and it requires eating many protein-rich foods, such as:
- Lean meats
- Poultry
- Fish and seafood
- Eggs
- Legumes
- Nuts
- Tofu
Potential Benefits of High Protein Diets for Weight Management
Evidence suggests high-protein diets lead to weight loss and improve body composition by maintaining lean body mass.Β
Protein helps increase metabolism in several ways:
- Protein necessitates more energy to metabolize (referred to as the thermic effect of food)
- Protein helps maintain lean body mass, which is more metabolically active at rest.Β
Protein also helps with weight loss by increasing fullness, which helps reduce overall calorie intake. This can improve insulin sensitivity and overall metabolic health.
Insulin Resistance & High Protein Diets: What Does the Research Say?
High Protein Diets and Insulin Sensitivity
High-protein, calorie-restricted diets have been shown to positively impact insulin resistance in the short term in patients of a healthy weight and patients with overweight and obesity. By increasing satiety and reducing overall intake, high-protein diets promote weight loss, which improves insulin sensitivity.Β
In addition, protein helps maintain glucose homeostasis. The breakdown of amino acids is insulinotropic. This means it acts on alpha and beta cells in the pancreas, as well as the enteroendocrine system, to produce anorexigenic (appetite-reducing) neuroendocrine hormones, like glucagon-like peptide-1, glucose-dependent insulinotropic peptide, somatostatin, and others.
Although high-protein diets have been shown to improve insulin resistance in patients with overweight and obesity, evidence suggests they may induce insulin resistance in patients of healthy weight in the long term (> 6 months).
The proposed mechanisms include the long-term elevation of branched-chain amino acids and blunting insulin receptor activity. Additional studies are needed on the effects of long-term high-protein, calorie-restricted diets on insulin sensitivity within different populations.
The Role of Protein Source
Different sources of protein have significant impacts on insulin resistance and overall health. While animal- and plant-based proteins provide various benefits, plant-based protein sources provide higher fiber and polyphenol contents.Β
In addition, animal proteins have more branched-chain amino acids, which, in excess, are associated with insulin resistance. Balancing protein intake from various sources can optimize insulin sensitivity for long-term metabolic health.
Potential Downsides of High Protein Diets
High-protein diets, especially animal protein, may cause health concerns over the long term.Β
- A high intake of animal fats can increase cardiovascular disease risk.Β
- Increased demand for the kidneys to excrete protein can increase the glomerular filtration rate, causing renal hypertrophy (enlargement of the kidneys).
- High protein intake over time may increase bone resorption due to increased urinary calcium excretion.
- Excess protein intake in the long term could contribute to insulin resistance.
Balancing Protein Intake
When following a high-protein diet, prioritize not only the quantity but also the quality of protein. Focus on lean meats, fish and seafood, nuts, and plant-based proteins, which will provide lean protein and healthy fats.Β
A low-to-moderate carbohydrate intake should include complex carbohydrate sources rich in fiber and polyphenols, such as veggies, fruits, whole grains, and legumes, which provide important nutrients for overall health.
Alternative Dietary Approaches
Aside from high-protein diets, there are several alternative diets to help manage insulin resistance, including the Mediterranean diet, Dietary Approaches to Stop Hypertension (DASH) diet, and intermittent fasting (IF), or time-restricted feeding (TRF).
The Mediterranean diet emphasizes whole foods, fruits and vegetables, whole grains, fish and seafood, nuts and seeds, and extra virgin olive oil. It minimizes added sugars, processed foods, and red meat. The Mediterranean diet has been shown to have various health benefits, including weight loss and enhanced insulin sensitivity by increasing levels of the neuroendocrine hormones glucagon-like peptide-1 (GLP-1) and oxyntomodulin.
The DASH diet was initially developed to treat hypertension by promoting low-fat, lower-sodium intake. It has also demonstrated efficacy in treating hyperlipidemia, improving insulin resistance, and promoting modest weight loss.
IF and TRF have demonstrated positive effects on metabolism, controlling insulin release, and regulating other anorexigenic neuroendocrine hormones like GLP-1 and oxyntomodulin. However, the evidence regarding their long-term success in weight loss is unclear.
Recommendations for a Balanced Diet
Balancing lean protein from animal- and plant-based sources, complex carbohydrates, and healthy fats within a controlled calorie diet is the best approach for improving insulin resistance and maintaining optimal nutrition.Β
Selecting nutrient-dense, natural foods like fruits, vegetables, whole grains, healthy fats, and lean proteins, and limiting added sugars, refined carbohydrates, and processed foods helps maintain a balanced diet. Adopting a personalized approach to a high-protein diet helps optimize protein quality and quantity in the context of insulin resistance.
Combining dietary changes with other lifestyle modifications is vital in treating insulin resistance. Engaging in regular physical activity, properly managing stress, and achieving adequate sleep improves insulin sensitivity. Incorporating these factors can improve insulin sensitivity and bolster weight loss more than dietary modifications alone.Β
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Key Takeaways
- Insulin resistance increases the risk of developing chronic diseases, including diabetes, cardiovascular disease, metabolic syndrome, and obesity.Β
- Several dietary approaches may improve glycemic control and insulin sensitivity. Incorporating a high-protein diet suggests a clear benefit for managing insulin resistance.Β
- However, tailoring personalized nutrition approaches for each patient is essential to maximize weight loss success while preventing the potential disadvantages of generic diets.Β
- Applying individualized dietary recommendations with holistic lifestyle changes can deliver optimal long-term metabolic health.