Hormones and weight:  with more than 70% of Americans overweight or obese (NIDDKD, 2021), many people struggle to understand what is happening to their bodies.  

A common concern for many people struggling with weight is the state of their hormones, and how hormonal factors may be at the root of their difficulties with weight management.

While many people express concerns about their “hormones” impacting their ability to lose weight, many people feel lost concerning exactly what hormones are playing a role, and what interventions they can take to regain control of their weight.

When discussing hormones and weight management, commonly estrogen, progesterone, thyroid hormones, and even testosterone are discussed.  However, many people struggling with their weight overlook one of the most important hormones affecting their body weight–insulin.

Insulin resistance and weight gain

For more than 100 years, insulin has been recognized as an anabolic stimulant that leads to weight gain (Kolb et al., 2020).  In fact, insulin was used in low doses to promote weight gain in persons suffering from conditions that caused lack of appetite and undernutrition (Kolb et al., 2020). 

Further evidence of insulin’s effect on promoting fat storage and interfering with fat breakdown is noted when infusions of low dose insulin reduces fat breakdown in muscle by 43% and in fatty tissue by 75% (Kolb et al., 2020).  

Within the human body, mild increases of insulin above normal fasting levels (less than required to stop your body from producing new glucose), fat metabolism decreases substantially while fat production and storage increase significantly (Kolb et al., 2020).

Accordingly, chronically elevated fasting insulin levels as well as elevated insulin levels through the course of the day promote weight gain, new fat tissue creation, increase the risk of obesity, and inhibit fat breakdown (Kolb et al., 2020).

Humans and mice with higher fasting insulin levels gain weight more rapidly (Kolb et al, 2020).  

Insulin resistance leads to higher overall insulin levels (Freeman et al., 2023).  Factors that contribute to development of insulin resistance include: 

• Excess visceral fat
• BMI over 25
• Aging process
• Lack of physical activity
• Calorie excess
• Certain medications, including SSRI’s, antipsychotic medications, glucocorticoid steroids
• High sodium diets
• High blood levels of free fatty acids due to excess body fat, high fat diets, or high fat breakdown
• Polycystic ovarian syndrome (PCOS)
• Certain genetic conditions and personal or family history of diabetes, heart disease, or hypertension

Prevalence of insulin resistance in the U.S. population is estimated to affect at least 40% of adults (Freeman et al., 2023).  Without meaningful interventions, insulin resistance can progress to type 2 diabetes.  NOTE:  you do NOT have to have diabetes or prediabetes to experience insulin resistance and its effects (CDC, 2024).  

Interventions to address insulin resistance

According to the Diabetes Prevention Program and its Outcomes Study (DPP & DPPOS), lifestyle interventions were effective at preventing development of diabetes in persons with insulin resistance by doing the following (Freeman et al., 2023):  

• • Dietary therapy with sodium reduction, fat reduction, calorie restriction, and choosing lower glycemic index foods.  (NOTE:  whole food plants such as beans, whole grains, most fruits and vegetables, mushrooms, herbs/ spices, and unsweetened teas/ coffee naturally meet these criteria).
  • Personalized supportive programs to support nutrition, fitness, and weight loss goals 
  • Weight loss of at least 7% of body weight (reduces diabetes risk by 58%)
  • Metformin which reduces risk of diabetes by 31%

Additional lifestyle interventions for insulin resistance include: 

• Low fat 100% whole food plant-based diet–several randomized controlled trials using whole food plant based diet interventions demonstrated the following outcomes (Kahleova et al., 2020; Bernard et al., 2022; Bernard et al., 2009):
  • • Significant improvement in blood sugar levels and A1C levels 
    • Significant improvements in insulin levels, 
    • Significantly improved oral glucose challenge test results
    • Weight reduction by 13-14 lbs in 16 weeks without tracking calories and without an exercise or medicine intervention
    • Superior outcomes versus the American Diabetes Association’s own diet and the Mediterranean diet
    • These results were achieved WITHOUT calorie restriction, portion control, and without medication or exercise interventions
• Physical activity (Bird & Hawley, 2017):
  • Every 500 calories burned during physical activity per week correlates to a 9% reduction in diabetes risk, suggesting a dose effect (more =’s more protection)
  • Improvements in insulin sensitivity occur during and after exercise, with improvements lasting up to 72 hours 
  • A combination of doing both strength training and aerobic exercise throughout the week may be more effective than either form of exercise alone

What about seafood and dairy?

Insulin resistance promotes weight gain, and further weight gain promotes increased insulin resistance.  

Therefore, swapping seafood (which generally has less calories per oz) in place of other meats reduces the risk of diabetes and can further support weight loss efforts (Liaset et al., 2019).  

Even at equal calorie intake levels, consumption of seafood instead of other forms of meat improves insulin sensitivity as measured in post meal glucose and fasting glucose testing (Liaset et al., 2019).  

This may be due to effects of omega-3 fatty acids and reductions in body wide inflammation or due to other nutrient components in seafood–the exact mechanisms are not yet fully understood (Liaset et al., 2019). 

Dairy intake and insulin resistance/ risk of diabetes research is mixed.  Some studies show as dairy intake goes up, insulin resistance/ diabetes risk goes down, while other studies show no effects or even worsening insulin resistance as dairy foods increase (Turner, Keogh, & Clifton, 2015).  Some of the inconsistencies can be explained that in many of the studies, weight loss was also a component of the study, which alone can explain improvements in insulin sensitivity independent of effects of dairy (Turner et al, 2015).

Some of the inconsistencies can be explained that in many of the studies, weight loss was also a component of the study, which alone can explain improvements in insulin sensitivity independent of effects of dairy (Turner et al, 2015).  

As animal protein gets replaced by plants, diabetes rates go down…

While replacing animal meat with seafood, and consuming dairy as part of a weight loss diet may improve insulin sensitivity, it is telling that as animal protein is progressively removed from the diet, insulin sensitivity correspondingly improves (Olfert & Wattick, 2018).

Studies on diabetes prevalence in the health conscious, more plant-based Seventh-Day Adventist population over a 17-year period noted that:

• Just one serving of meat per week on average raised diabetes risk by 29% versus those that ate no meat…this rose to 38% higher if that meat was processed meat.
• Lifelong vegetarian patterns decreased diabetes risk by 74% compared to those that ate meat at least one time per week! (Olfert & Wattick, 2018). 

In the same population group, as animal protein increased, diabetes prevalence also increased.  Prevalence rates of diabetes in the Seventh-day Adventist population were as follows:  

• Vegans had a 2.9% prevalence of diabetes
• Vegetarians (add in dairy and eggs) had a 3.2% prevalence of diabetes
• Pesco-vegetarians (add in seafood) had a 4.8% prevalence of diabetes
• Non-vegetarians had a 7.6% prevalence of diabetes (Olfert & Wattick, 2018). 

A diet based on lean animal protein foods, fruits and vegetables, and healthier fats from olive oil, nuts and seeds (such as the Mediterranean diet or DASH diet) certainly beats a diet full of fatty meats, red meats, processed meats, and refined grains/ added sugars.  

However, both population studies and randomized controlled trials show that progressively replacing animal proteins altogether with whole food plants gives the best protection against insulin resistance (Olfert & Wattick, 2018).  

This is particularly interesting as many people erroneously believe that the answer to insulin resistance is to restrict carbohydrates, when in fact, it’s through diets rich in complex whole food carbohydrates that we see the best protection.

Functional foods that can improve insulin sensitivity 

As noted above, a whole food plant-based diet has repeatedly demonstrated efficacy at improving insulin resistance.  But what foods, herbs, and spices  pack the biggest punch in the fight against insulin resistance?  

Whole grains

• Whole grains (such as brown rice, rye, barley, quinoa, oatmeal, etc) contain protective compounds such as soluble and insoluble fibers, inulin, β-glucan,carotenoids, phytates and phytoesterogens, phenolic acids, and tocopherols that have been shown to lower the risk of (Mirmiran, Bahadoran, & Azizi, 2014).: 
  • Obesity, 
  • Type 2 diabetes,
  • Cardiovascular diseases, 
  • Hypertension, 
  • Metabolic syndrome 
  • Certain cancers

Whole grain compounds also:

• Lower cholesterol, 
• Improve blood sugar regulation,
• Improve pancreatic beta-cell function, 
• Promote the growth of healthy gut microbiota such as lactobacillus and bifidobacteria, 
• Stimulate natural production of GLP-1, 
• Reduce hunger hormones (Mirmiran, Bahadoran, & Azizi, 2014).

Fruits and vegetables 

• Phytochemical rich fruits and vegetables contain soluble and insoluble fiber along with anthocyanins, polyphenols, flavonoids, and numerous bioactive compounds that do the following (Mirmiran, Bahadoran, & Azizi, 2014):
  • • Lower blood pressure, 
    • Lower blood sugar including reducing spikes in blood sugar following meals, 

• Lower cholesterol,

• • Improve blood vessel function 
  • Boost antioxidant defenses in the body.  

 

• The following fruits and vegetables are particularly rich in these health promoting phytochemicals: 
  • Tomatoes and tomato byproducts
  • Grapefruit (caution consuming this if on medications due to numerous dangerous medication interactions)
  • Watermelon
  • Red apples (the peel is particularly rich in bioactive compounds)
  • Berries of all types
  • Grapes
  • Pomegranates
  • Garlic/Onions
  • Cherries
  • Cabbage & Cauliflower
  • Citrus fruits
  • Spinach
  • Pumpkin
  • Prunes 
  • Carrots
  • Mangos
  • Dates
  • Barberries (the source of berberine–noted below under herbs)
  • Figs

Beans, soy, and lentils 

Beans and lentils contain soluble and insoluble fibers, resistant slow-digesting starches, and α-amylase inhibitory peptides that: 

• Decrease absorption and digestion of carbohydrates, 
• Reduce post meal blood sugar levels, 
• Lower cholesterol, 
• Protect against fatty liver, 
• Reduce risk of obesity (Mirmiran, Bahadoran, & Azizi, 2014).

In fact, beans are so powerful in lowering blood sugar that they have been compared to diabetic medications in efficacy (Mirmiran, Bahadoran, & Azizi, 2014)!! 

Soy protein and soy beans have been shown to:

• Improve hormone profiles related to the thyroid, and insulin to glucagon ratios 
• Anti-inflammatory
• Promotes lower blood pressure
• Boost insulin sensitivity, 
• Inhibit enzymes used to produce harmful apolipoproteins implicated in heart disease and plaques (Mirmiran, Bahadoran, & Azizi, 2014).  

Nuts

Nuts have numerous cardioprotective and anti-diabetic properties.  Consumption of nuts:

• Lowers post-meal glucose levels, 
• Lowers inflammatory responses after meals, 
• Anti-inflammatory
• Improves insulin sensitivity (Mirmiran, Bahadoran, & Azizi, 2014).  

Nuts contain higher levels of l-arginine, health promoting fatty-acids, which can support nitric oxide production and relaxation of blood vessels.  

Nuts may reduce the risk of cardiovascular disease as well (Mirmiran, Bahadoran, & Azizi, 2014). 

Spices and herbs shown to improve insulin sensitivity

Note, the use of herbs and spices at clinical doses may produce medication interactions or unknown side effects.  Herbs and supplements should always be discussed with your pharmacist or medical provider, especially if you are pregnant, take any medications, or have any health conditions.  

The following spices have been shown in research studies to improve insulin sensitivity (Mackonochie et al., 2023):  

Cardamom:  multiple high-quality double-blinded randomized controlled trials show cardamom improves glucose levels, A1C levels, and inflammatory markers.

• Dose in studies:  3 grams in capsules daily

Cinnamon:  many studies have been completed on cinnamon, including multiple high-quality double-blinded randomized controlled trials.  While study results are at times mixed, many well conducted studies show cinnamon lowers A1C, fasting glucose levels, fasting insulin levels, among other effects.  There are some concerns about a natural liver toxin–coumerin–found in cinnamon if consumed in excess.  Lower doses may be safer.  

• Dose in studies:  0.5 grams / day up to 6 grams per day in capsules

Cumin:  a randomized-controlled trial of 88 women noted that weight, cholesterol, waist circumference, and fat mass were reduced significantly in the group taking cumin compared to the control group. 

• Dose in study: 6 grams / day (study lasted 12 weeks, 3g in yogurt twice daily versus control group consuming just yogurt twice daily)

Fenugreek: multiple high-quality double-blinded placebo controlled studies found that compared to a placebo group, fenugreek significantly lowered cholesterol levels, A1C, fasting blood sugar levels, and triglycerides.

• Dose in studies:  many of the high quality studies used 10 g/ day

Garlic:  multiple high-quality double-blinded placebo controlled studies found that garlic lowers triglyceride levels, insulin levels, and fasting blood sugar levels.  

• Dose in studies:  many of the high quality studies used 1.6 g/ day

Ginger:  multiple high-quality double-blinded placebo controlled studies found ginger lowers inflammatory markers, cholesterol and triglycerides, improves insulin sensitivity, lowers fasting blood sugar, and lowers insulin levels.  

• Dose in studies:  1-3 g/ day

Nigella seeds (black cumin):  multiple high-quality double-blinded placebo controlled studies found black cumin seeds lower body weight, cholesterol and triglycerides, A1C, and fasting blood sugar.  However, study results varied with most studies finding benefits. Inconsistencies on blood sugar versus cholesterol improvements versus both parameters improving are noted between studies.  

• Dose in studies:  1-3 g/ day

Turmeric:  multiple high-quality double-blinded placebo controlled studies found turmeric improves fasting blood sugar and lowers insulin levels.  

• Dose in studies:  2-3 g/ day

Berberine:  several studies pitted berberine against a placebo in one study of diabetics or against metformin in another study involving diabetics.  Both studies found berberine was effective at lowering all parameters of blood sugar including A1c, fasting blood sugar, after-meal (postprandial) blood sugars, and insulin levels (Och et al., 2022).  

These reductions in blood sugar levels for berberine were on par with metformin.  Not only that, but the berberine also lowered cholesterol levels, outperforming the metformin (Och et al., 2022).   

Summary

Insulin resistance is a common factor highly prevalent in the American population.  Insulin resistance leads to higher baseline insulin levels as the body works to overcome the insulin resistance.  

Even mild increases in baseline insulin levels can interfere with fat breakdown and promote fat storage.  Therefore, those desiring to lose weight need to consider strategies to improve insulin sensitivity.

Fortunately, nutrition patterns heavily centered around healthy plant-based foods:  whole grains, beans, brightly colored fruits and vegetables, herbs and spices, can substantially improve insulin sensitivity.  

Exercise can play a further supportive role.

Substantive weight loss can go a long way in improving insulin sensitivity and decreasing diabetes risk and improving insulin sensitivity.

Finally, metformin can improve insulin sensitivity and decrease diabetes risk by more than 30%.

A combined approach is key.

How we can help

At Lancaster Wellness, we use a multi-pronged approach to help clients lose weight.  Many of these approaches address insulin resistance.

With nutrition coaching, access to group fitness classes locally, or personalized movement programs, use of appropriate medications, structure, support, accountability, meal plans, recipes, and more, our clients frequently see their health markers and weight improve substantially.  

A1C levels come down substantially when elevated, and for clients simply struggling to lose fat “no matter what they do,” the fat finally comes off.  Particularly when they embrace the lifestyle aspects of the program which support insulin sensitivity.  

Written by Donovan Carper MSN RN CPT CHC

References

Barnard, N. D., Alwarith, J., Rembert, E., Brandon, L., Nguyen, M., Goergen, A., Horne, T., do Nascimento, G. F., Lakkadi, K., Tura, A., Holubkov, R., & Kahleova, H. (2022). A Mediterranean Diet and Low-Fat Vegan Diet to Improve Body Weight and Cardiometabolic Risk Factors: A Randomized, Cross-over Trial. Journal of the American Nutrition Association, 41(2), 127–139. https://doi.org/10.1080/07315724.2020.1869625 

Barnard, N. D., Cohen, J., Jenkins, D. J., Turner-McGrievy, G., Gloede, L., Green, A., & Ferdowsian, H. (2009). A low-fat vegan diet and a conventional diabetes diet in the treatment of type 2 diabetes: a randomized, controlled, 74-wk clinical trial. The American journal of clinical nutrition, 89(5), 1588S–1596S. https://doi.org/10.3945/ajcn.2009.26736H

Bird, S. R., & Hawley, J. A. (2017). Update on the effects of physical activity on insulin sensitivity in humans. BMJ open sport & exercise medicine, 2(1), e000143. https://doi.org/10.1136/bmjsem-2016-000143   

Freeman AM, Acevedo LA, Pennings N. Insulin Resistance. [Updated 2023 Aug 17]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK507839/ 

Kolb, H., Kempf, K., Röhling, M., & Martin, S. (2020). Insulin: too much of a good thing is bad. BMC medicine, 18(1), 224. https://doi.org/10.1186/s12916-020-01688-6 

Kahleova, H., Petersen, K. F., Shulman, G. I., Alwarith, J., Rembert, E., Tura, A., Hill, M., Holubkov, R., & Barnard, N. D. (2020). Effect of a Low-Fat Vegan Diet on Body Weight, Insulin Sensitivity, Postprandial Metabolism, and Intramyocellular and Hepatocellular Lipid Levels in Overweight Adults: A Randomized Clinical Trial. JAMA network open, 3(11), e2025454. https://doi.org/10.1001/jamanetworkopen.2020.25454

Liaset, B., Øyen, J., Jacques, H., Kristiansen, K., & Madsen, L. (2019). Seafood intake and the development of obesity, insulin resistance and type 2 diabetes. Nutrition research reviews, 32(1), 146–167. https://doi.org/10.1017/S0954422418000240 

Mirmiran, P., Bahadoran, Z., & Azizi, F. (2014). Functional foods-based diet as a novel dietary approach for management of type 2 diabetes and its complications: A review. World journal of diabetes, 5(3), 267–281. https://doi.org/10.4239/wjd.v5.i3.267 

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDKD). (2021). Overweight & obesity statistics. Retrieved from https://www.niddk.nih.gov/health-information/weight-management/adult-overweight-obesity/definition-facts  

Och, A., Och, M., Nowak, R., Podgórska, D., & Podgórski, R. (2022). Berberine, a Herbal Metabolite in the Metabolic Syndrome: The Risk Factors, Course, and Consequences of the Disease. Molecules (Basel, Switzerland), 27(4), 1351. https://doi.org/10.3390/molecules27041351

Olfert, M. D., & Wattick, R. A. (2018). Vegetarian Diets and the Risk of Diabetes. Current diabetes reports, 18(11), 101. https://doi.org/10.1007/s11892-018-1070-9  

CDC.gov. (2024, May 14). About insulin resistance and type 2 diabetes.  Retrieved from https://www.cdc.gov/diabetes/about/insulin-resistance-type-2-diabetes.html 

Turner, K. M., Keogh, J. B., & Clifton, P. M. (2015). Dairy consumption and insulin sensitivity: a systematic review of short- and long-term intervention studies. Nutrition, metabolism, and cardiovascular diseases : NMCD, 25(1), 3–8. https://doi.org/10.1016/j.numecd.2014.07.013