What diet reduces IGF-1 levels? Exploring plant-based, ketogenic, and fasting approaches

November 18, 2025 •

4 min read

According to a systematic review published in Ageing Research Reviews, certain dietary interventions can effectively lower serum IGF-1 levels. This comprehensive guide explores what diet reduces IGF-1 levels, detailing specific approaches proven to help modulate this important hormone for better health and longevity.

Quick Summary

This article examines dietary strategies for reducing insulin-like growth factor 1 (IGF-1), a hormone linked to aging and certain diseases. It details the effects of plant-based diets, caloric restriction, intermittent fasting, and ketogenic diets on IGF-1 levels and explains the metabolic mechanisms involved.

Key Points

Embrace Plant-Based Eating: Adopting a vegan or primarily plant-based diet has been shown to significantly lower IGF-1 levels compared to meat-eaters and vegetarians.
Reduce Animal Protein: Minimizing intake of high-quality animal proteins, including red meat and dairy, is crucial, as they are strong promoters of IGF-1.
Practice Intermittent Fasting: Intermittent or periodic fasting can effectively reduce circulating IGF-1 levels by triggering a metabolic shift.
Lower Glycemic Load: Controlling insulin spikes by following a low glycemic index and load diet can help modulate IGF-1 production.
Balance Protein Intake by Age: Research suggests different protein strategies may be optimal depending on age, with lower protein intake being beneficial for middle-aged adults.
Focus on Whole Plant Foods: Prioritizing a diet rich in legumes, nuts, seeds, and vegetables is an effective way to lower IGF-1 while ensuring adequate nutrition.

Insulin-like growth factor-1 (IGF-1) is a hormone primarily produced in the liver that plays a critical role in childhood growth and anabolic processes. While essential for development, persistently high levels in adulthood have been associated with an increased risk of certain diseases, including some cancers. For this reason, many are interested in what diet reduces IGF-1 levels as a potential strategy for disease prevention and healthy aging. The key to modulating IGF-1 through diet lies in controlling the intake of specific macronutrients that drive its production, namely protein and carbohydrates.

The Strong Link Between Animal Protein and IGF-1

Research consistently shows a positive correlation between the consumption of animal protein and elevated IGF-1 levels. This is believed to be due to the specific amino acid composition of animal proteins, which closely resembles our own and signals the body to accelerate cellular growth. The evidence is particularly strong for dairy products, which are high in both protein and insulinemic components, and have been shown to significantly increase IGF-1. A landmark study involving 292 women found that vegans had a 13% lower mean serum IGF-1 concentration compared to meat-eaters and vegetarians. Another study in middle-aged adults linked high animal protein intake to a significantly higher risk of all-cause and cancer mortality. By swapping animal proteins for plant-based alternatives, it is possible to reduce this signaling pathway.

Low-Protein, Plant-Based Diets

Adopting a low-protein, plant-based diet is one of the most effective ways to lower IGF-1. This eating pattern minimizes the high-quality protein from animal sources that most efficiently triggers IGF-1 production. A diet rich in plant-based proteins from sources like legumes, seeds, nuts, and whole grains provides essential nutrients without over-activating the growth-promoting pathways linked to high IGF-1. Such diets have been shown to not only reduce circulating IGF-1 but also increase the levels of IGF-binding proteins (IGFBP), which help neutralize excess IGF-1 in the bloodstream.

Practical Steps for a Plant-Based Diet

Swap dairy milk: Replace cow's milk with unsweetened plant-based alternatives like almond, soy, or cashew milk.
Embrace legumes: Integrate beans, lentils, and peas into your meals as a primary protein source. Chili, soups, and curries are great options.
Use tofu and tempeh: These soy-based foods are versatile protein sources that don't spike IGF-1 like animal proteins.
Increase greens: Focus on vegetables, especially leafy greens, which provide nutrients and fiber with very little protein.

Intermittent and Periodic Fasting

Fasting, particularly intermittent fasting (IF) and periodic fasting, has been shown to significantly reduce IGF-1 levels. Short-term periods of fasting trigger a metabolic shift that decreases circulating IGF-1 and its signaling pathways. This effect is independent of total calorie restriction, as some studies found that fasting regimens lowered IGF-1 more effectively than continuous energy-restricted diets.

How Fasting Affects IGF-1

Periodic Fasting: Studies on Fasting-Mimicking Diets (FMDs) have demonstrated a significant reduction in IGF-1, along with an increase in the IGF-1 inhibitor IGFBP-1.
Intermittent Fasting: Regimens like the 16:8 method (16 hours fasting, 8 hours eating) can also help to keep insulin and IGF-1 levels in check.
Stem Cell Regeneration: Fasting cycles have been shown to trigger a regeneration process in the body and a dramatic drop in IGF-1.

The Role of Low Glycemic Index Diets

Diets high in refined carbohydrates and sugar, common in the Western diet, cause spikes in blood glucose and insulin. High insulin levels can indirectly stimulate IGF-1 production, potentiating its effects. Adopting a low glycemic index (GI) and low glycemic load (GL) diet can help mitigate these effects. A randomized controlled trial showed that participants on a low GI/GL diet experienced a significant decrease in IGF-1 concentrations over a two-week period.

Comparison of Diets for IGF-1 Reduction


Dietary Strategy	Primary Mechanism	Effect on IGF-1	Best For	Considerations
Plant-Based	Lowers high-quality animal protein intake, increases fiber.	Significant and sustained reduction over time.	Long-term lifestyle change, consistent results.	Requires careful planning to ensure balanced nutrition.
Ketogenic Diet	Restricts carbohydrates, lowers insulin levels.	Effective at reducing IGF-1 by about 20% in some studies.	Short-term intervention, strict carbohydrate control.	Not suitable for everyone, potential nutrient deficiencies.
Intermittent Fasting	Cycles between eating and fasting windows, lowers insulin.	Acute, significant drops during fasting periods.	Flexible and can be combined with other diets.	Can cause initial hunger and fatigue, requires adaptation.
Low Glycemic	Reduces post-meal glucose and insulin spikes.	Modest, but consistent reduction.	For managing blood sugar while lowering IGF-1.	Less impactful on its own compared to combined strategies.

Conclusion

While there is no single magical food or diet that instantly eliminates IGF-1, several proven dietary strategies can significantly help reduce its levels. The most consistently supported approach involves adopting a low-protein, plant-based diet, which lowers IGF-1 levels by reducing the specific amino acid triggers found in animal products. Combining this with intermittent fasting or a low glycemic approach can offer even more pronounced effects by controlling insulin and promoting metabolic switches that are conducive to lower IGF-1. Ultimately, a balanced, whole-foods diet emphasizing plants is a powerful tool for modulating IGF-1 and fostering long-term health and longevity. It is recommended to consult with a healthcare provider before making drastic dietary changes, particularly for those with existing health conditions.

Foods that reduce IGF-1

Vegetables and leafy greens: Rich in nutrients and fiber, with very low protein density.
Legumes: Beans, lentils, and chickpeas are excellent plant-based protein sources.
Nuts and seeds: Provide protein, healthy fats, and fiber without the IGF-1 spike of animal protein.
Berries: Foods like blueberries offer antioxidants and have a low glycemic load.
Whole grains: Opt for whole grains over refined carbohydrates to manage insulin levels.

Foods that raise IGF-1

Dairy products: Milk and fermented dairy are highly insulinemic and increase IGF-1.
Meat and eggs: Animal proteins, especially red meat, have a strong link to higher IGF-1 levels.
High-glycemic carbohydrates: Refined grains and sugary foods cause blood sugar and insulin spikes, which can affect IGF-1.
Excessive protein: Overconsumption of protein, especially from animal sources, is a major driver of IGF-1 production.

Frequently Asked Questions

IGF-1 stands for Insulin-like Growth Factor 1. It is a hormone that promotes cellular growth and repair. While vital for development, excessively high levels in adulthood have been linked to an increased risk of chronic diseases like cancer, making dietary control a health priority.

Yes, studies have shown that individuals following a vegan diet tend to have significantly lower IGF-1 levels compared to those who eat meat or are vegetarian. This is primarily due to a lower intake of animal protein.

Yes, both intermittent and periodic fasting have been shown to reduce IGF-1 levels. Fasting-mimicking diets, for example, can cause a significant drop in circulating IGF-1, even with partial calorie restriction.

Animal proteins have an amino acid profile that closely resembles human amino acids, which sends a stronger signal to the body to increase growth factor production. Plant proteins, while providing necessary amino acids, do not trigger the same high level of response.

To lower IGF-1, you should limit or avoid foods high in animal protein, including dairy, meat, and eggs. High-glycemic, refined carbohydrates should also be minimized as they cause insulin spikes that can indirectly raise IGF-1 levels.

Yes, especially in older age. Low IGF-1 is beneficial in middle age but can become detrimental in individuals over 75, potentially affecting bone density, brain health, and muscle mass. The goal is moderation, not complete elimination.

Changes can occur relatively quickly. For instance, some studies have shown significant reductions in IGF-1 levels after just a couple of weeks on a low glycemic or plant-based diet. Longer-term adherence leads to more stable and pronounced results.