What can I eat?

If you ever received a diagnosis of prediabetes or diabetes, you likely asked yourself, “What can I eat?” You are not alone. Despite widespread interest in evidence-based dietary recommendations to improve metabolic health, we continue to be in an era of contradictory nutrition information.  There is no agreement on the ideal daily caloric intake of carbohydrates, proteins and fat to prevent or reverse diabetes.

The good news is that there are consistent findings across published intervention trials, observational studies and meta-analyses of the metabolic health benefits of a variety of whole-food plant-based diets, some of which include animal products, such as the Mediterranean-style and low-carbohydrate diets. There is evidence of the benefits of whole grains, legumes, nuts, fruits, and vegetables and of the adverse effects of refined and processed foods.¹²³⁴

Below, we have identified three key recommendations,⁵ consistent across numerous studies and diets. So, what can you eat? The consensus is that the best way to achieve metabolic health through diet is to:

• Eat unprocessed whole foods
• Emphasize non-starchy vegetables
• Limit added and refined sugars  

Consume Unprocessed Whole Foods

Starting in the 1900s, the standard Western diet popularized ready-to-eat meals and processed foods. By 2012, up to 60% of calories consumed by Americans were considered ultra-processed.⁶  Unfortunately, in spite of their convenience and affordability, these processed animal and plant foods, stripped of their nutrient value and often combined with added sugar, are far from their natural state and suboptimal for health. These processed foods, made with refined grains and flour, such as chips, cereal, crackers, and white bread, cause sharp rises in blood sugar levels, known as glucose spikes, that ultimately lead to metabolic dysfunction.

You can think of metabolic dysfunction as your body—after digesting proteins, carbohydrates and fats and turning them into sugar- and acid-based fuels—being unable to properly use these fuels for immediate or stored energy. In the case of diabetes, for example, the glucose that your body has produced is unable to get into the cells. This causes your blood sugar level to rise, resulting in your pancreas working more to produce more insulin, the key to unlocking the doors to your cells and allowing the glucose to get used. 

One of the most important ways to achieve metabolic health and reduce inflammation,⁷ is to eat a diet rich in nutritious, unprocessed foods, free of chemical additives. Whole foods include fiber and protein-rich foods including legumes (e.g., beans and lentils), nuts (e.g., almonds, walnuts, pecans, Brazil nuts, macadamia nuts, and pistachios), seeds (e.g., pumpkin, chia, flax, sunflower, hemp, and sesame), animal protein (e.g, meat, poultry, fish, egg), dairy products (e.g., cheese, cottage cheese, yogurt) and tofu/tempeh. Fats in their natural form include nuts, seeds, avocado, coconut, and olives.

The best ways to consume unprocessed whole foods:

• Make one addition per week. Start with a small step like adding a new vegetable or new vegetable side-dish to one of your meals.
•  Make one replacement per week. Swap one processed snack with a healthier version of it or a different snack altogether.
•  Remove one item per week. Cut out one excess snack, such as a second bowl of cereal, a can of soda, a cookie, or fast-food French fries.
•  Scroll through Blueberry’s recipes and enjoy some of your own home-made cooked meals.

Remember, each change you make gets you closer to achieving your metabolic and health goals.

Emphasize Non-Starchy Vegetables

Most people do not consume the minimum non-starchy vegetable requirement each day of two to three cups.⁸ Instead, they often bulk up on starchy vegetables, including potatoes, sweet potatoes, corn, beans, lentils, peas, yams and winter squashes. These starchy vegetables often are less satiating and can trigger your brain to want more.

Non-starchy fiber-rich vegetables—including leafy greens, broccoli, mushrooms, peppers, onions, beets, carrots, cauliflower, zucchini, and Brussels sprouts—are low in carbohydrates, rich in vitamins and minerals, and signal to your brain that you are full. Additionally, they are shown to benefit your microbiome⁹ and reduce inflammation,¹⁰ two factors linked to metabolic health. 

The best ways to emphasize non-starchy vegetables:

• The next time you are hungry, search for recipes that highlight non-starchy vegetables.
•  Replace starchy vegetable side dishes with a non-starchy vegetable side dish.

Limit Excess Sugar

Despite its appeal, sugar has no nutritional value. The consumption of excess sugar, often referred to as fructose, can have dire consequences for your health, contributing to obesity and ultimately causing metabolic dysregulation and chronic health conditions. The presence of too much fructose in the body can cause mitochondrial dysfunction,¹¹ inflammation,¹² nonalcoholic fatty liver disease,¹³ and ultimately lead to insulin resistance¹⁴ and its sequalae, type 2 diabetes and heart disease.

Insulin is a hormone that is part of the body’s complex process of regulating glucose. Over consumption of sugar contributes to a less sensitive insulin response and ultimately insulin resistance, a bit like losing the key that opens your muscle, fat and liver cells to allow the glucose from your blood to enter.

As a result, you should avoid excess sugar consumption. If you want to cut out sugar from your diet, you first have to know where sugar is in your diet. Fructose not only occurs in whole fruits, which are high in water content and fiber and can be quite nutritious,¹⁵ it occurs in processed fruit, including fruit juice, which can harm your metabolic health over time. Fructose is also in high-fructose corn syrup, the most common sweetener in processed foods, honey, agave and maple syrup, and palm sugar. When fructose is mixed with glucose, it becomes table sugar, known as sucrose. Sugar is added to not only candy and soda, or traditional desserts like cake, pastries, and ice-cream, nor is it simply sprinkled on grapefruit or in your coffee, it is in ready-to-eat meals, energy bars, cereals, and yogurt. It is hidden in many of the meals you eat.

The best ways to avoid excess sugar: 

• Identify all the places where sugar is included in your diet. Pay close attention to food labels,¹⁶ which now include details on added sugar content.
• Start by cutting out those foods with sugar that you can easily do without.
• Eliminate juice, soda and other sugar sweetened beverages and replace them with water.
• Eat foods as close to their natural state as possible (e.g., an apple rather than applesauce, blueberries rather than blueberry pie, an orange rather than orange juice

The Bottom Line

An unprocessed plant-based diet, rich in nutrient-dense whole foods, high in low-starchy vegetables, and low in sugar can help you revert to a normoglycemic state, improving your metabolic health. 

References

1. Estruch R, Ros E, Salas-Salvadó J, et al. Primary prevention of cardiovascular disease with a Mediterranean diet supplemented with extra-virgin olive oil or nuts. N Engl J Med. 2018;378(25):e34.
2. Bloomfield HE, Koeller E, Greer N, MacDonald R, Kane R, Wilt TJ. Effects on health outcomes of a Mediterranean diet with no restriction on fat intake: a systematic review and meta-analysis. Ann Intern Med. 2016;165(7):491-500.
3. Stentz FB, Brewer A, Wan J, et al. Remission of pre-diabetes to normal glucose tolerance in obese adults with high protein versus high carbohydrate diet: randomized control trial. BMJ Open Diabetes Res Care. 2016;4(1):e000258.
4. Qian F, Liu G, Hu FB, Bhupathiraju SN, Sun Q. Association between plant-based dietary patterns and risk of type 2 diabetes: a systematic review and meta-analysis. JAMA Intern Med. 2019;179(10):1335-1344.
5. Evert AB, Dennison M, Gardner CD, et al. Nutrition therapy for adults with diabetes or prediabetes: a consensus report. Diabetes Care. 2019;42(5):731-754.
6. Baraldi LG, Steele EM, Canella DS, Monteiro CA. Consumption of ultra-processed foods and associated sociodemographic factors in the USA between 2007 and 2012: evidence from a nationally representative cross-sectional study. BMJ Open. 2018;8(3):e020574.
7. Pearson TA, Mensah GA, Alexander RW, et al. Markers of inflammation and cardiovascular disease: application to clinical and public health practice: a statement for healthcare professionals from the Centers for Disease Control and Prevention and the American Heart Association. circulation. 2003;107(3):499-511.
8. Lee SH, Moore LV, Park S, Harris DM, Blanck HM. Adults Meeting Fruit and Vegetable Intake Recommendations—United States, 2019. Morb Mortal Wkly Rep. 2022;71(1):1.
9. Li WZ, Stirling K, Yang JJ, Zhang L. Gut microbiota and diabetes: From correlation to causality and mechanism. World J Diabetes. 2020;11(7):293.
10. Tsalamandris S, Antonopoulos AS, Oikonomou E, et al. The role of inflammation in diabetes: current concepts and future perspectives. Eur Cardiol Rev. 2019;14(1):50.
11. Zhang DM, Jiao RQ, Kong LD. High dietary fructose: direct or indirect dangerous factors disturbing tissue and organ functions. Nutrients. 2017;9(4):335.
12. Jones N, Blagih J, Zani F, et al. Fructose reprogrammes glutamine-dependent oxidative metabolism to support LPS-induced inflammation. Nat Commun. 2021;12(1):1-13.
13. DiNicolantonio JJ, Subramonian AM, O’Keefe JH. Added fructose as a principal driver of non-alcoholic fatty liver disease: a public health crisis. Open Heart. 2017;4(2):e000631.
14. Softic S, Stanhope KL, Boucher J, et al. Fructose and hepatic insulin resistance. Crit Rev Clin Lab Sci. 2020;57(5):308-322.
15. Wallace TC, Bailey RL, Blumberg JB, et al. Fruits, vegetables, and health: A comprehensive narrative, umbrella review of the science and recommendations for enhanced public policy to improve intake. Crit Rev Food Sci Nutr. 2020;60(13):2174-2211.
16. Kim EJ, Ellison B, McFadden B, Prescott MP. Consumers’ decisions to access or avoid added sugars information on the updated Nutrition Facts label. PloS One. 2021;16(3):e0249355.