Blood Sugar, Diet Trends, and the Cortisol Connection – Midlife Health Part 2 with Keri Glassman

In Part 1 of this deep dive, Keri and I covered juicy topics that matter most for midlife health like GLP’s, seed oils, alcohol, protein consumption – and more! If you didn’t catch it, check out part 1 HERE.  Keri Glassman is a celebrity dietitian and is a go-to expert on nutrition for networks, other dietitians, and more. 

We are now here for Part 2 where we are cutting through the hype on blood sugar management, diet trends and the best way to eat (plus cataract surgery)! This candid discussion provides practical insights for anyone navigating their 40s, 50s, and beyond lead by two leading nutrition experts, Natalie Jill (a sports nutritionist) and Keri Glassman (a registered dietitian).

Cataract Surgery: Not Just for the Elderly

Keri recently underwent cataract surgery, surprising many who associate this procedure with much older adults. Many people associate cataracts with advanced age, but the clouding of the eye lens can actually begin developing as early as age 40. While most won’t require surgery until their 70s or 80s, some individuals may need intervention earlier. Cataract surgery a simple surgery where you typically do one eye at a time and it has very little recovery time, and the difference is immediate. The only complication she experienced was a slightly drooping eyelid (ptosis) after her first eye surgery, which occurs in a small percentage of patients. 

The Common Ground in Diet Trends 

All healthy diets, from paleo to vegan, are “pretty much the same”. While the specifics might differ, the foundations align across all healthy eating approaches:

• Whole, unprocessed foods form the foundation of any healthy diet
• Enough fiber and abundant vegetables and fruits provide essential phytonutrients, antioxidants, and fiber to help keep everything about us healthy 
• Quality protein sources support muscle maintenance, especially important during midlife
• Healthy fats contribute to hormone production and cell function
• Minimal added sugars and processed foods reduce inflammation
• Proper hydration supports all bodily functions

If you’re feeling good and your labs say you are healthy, there is no need to challenge what you’re eating. If you feel good, you’re doing the right thing for you. However, extreme approaches like carnivore diets that eliminate plant foods entirely raise concerns about micronutrient deficiencies and lack of fiber that supports gut health. These diets may temporarily improve certain conditions but typically don’t provide optimal nutrition for long-term health. Keri and I both agree that fruits and vegetables are super important for optimal health. If you’ve given up eating fruits and vegetables (like on carnivore diet) because you feel terrible eating them, it’s important to identify WHY this is happening, as there’s likely an underlying gut health issue that needs addressing. 

Similarly, with strict vegan diets, many (not all) people struggle to maintain optimal nutrition, especially adequate protein without overconsuming carbohydrates, and the increase of consumed grains can trigger inflammation, especially in someone with autoimmune. While some individuals thrive on plant-based diets, others struggle to maintain nutritional adequacy, particularly regarding protein, vitamin B12, iron, zinc, and omega-3 fatty acids.

The most sustainable dietary approach is typically one that:

• Includes a diverse range of nutrients
• Includes a plentiful amount of healthy fiber 
• Can be maintained consistently (approximately 360 days per year)
• Allows for social eating occasions
• Supports individual health markers and energy needs

Artificial Sweeteners 

These should be a NEVER in your diet. They are about 200-800x sweeter than sugar and they STILL trigger the insulin response even though you are not having actual sugar. Since you are triggering that response, your body is looking for the calories that typically come with the sugar that creates that response – but since you are not consuming them, you end up with even more sugar cravings later on. There is zero benefit to consuming these. 

Organic Food & Quality Over Convenience

While organic, grass-fed, and pasture-raised foods typically cost more, their nutritional benefits may justify the investment. Higher quality foods often contain:

• Greater nutrient density
• Fewer pesticide residues
• More beneficial fatty acid profiles (particularly in animal products)
• Higher antioxidant content
• Improved taste and satisfaction

So is organic better? Yes! Why? Because the amount of pesticides being sprayed on them is minimally less than those that are not! So YES, eating organic IS important…but it’s not organic or nothing. They are healthier for you AND they just simply taste better.  A lot of people argue that eating organic is too expensive, but there are really ways around making it possible.

Cost-effective strategies for accessing higher quality foods include:

• Prioritizing organic for the “dirty dozen” most contaminated produce items
• Shopping at farmers markets and direct-from-farm sources
• Using frozen organic options (which are often more economical…and can honestly be even healthier due to the way they are flash frozen)
• Reallocating budget from processed foods toward whole food ingredients

The Blood Sugar Connection

Having good metabolic health is a top priority for longevity and health span. Blood glucose regulation becomes increasingly important in midlife as insulin sensitivity naturally decreases. Poor blood sugar control contributes to numerous age-related conditions including:

• Cognitive decline and dementia
• Cardiovascular disease
• Cancer progression
• Accelerated aging
• Inflammation
• Hormonal imbalances

The more often you eat, the more often you are creating an insulin response in your body. The more you’re secreting insulin, the less you are in fat-burning mode. This is why fasting can be so beneficial – you’re giving your body a break from creating the insulin response so it can spend energy healing other things that need healing in your body.  

Important considerations for CGM users:

Blood sugar control is absolutely critical for everything from mood to preventing heart disease, cancer, and cognitive decline. Continuous glucose monitors (CGMs) are a tool you can use for understanding your personal responses to different foods. However, while CGMs can provide valuable insights, they should be used to identify patterns rather than triggering fear about individual food choices. It’s important to remember: 

• CGMs can be less accurate than finger-prick tests by 20-40 mg/dL
• Individual glucose responses vary significantly based on sleep, stress, exercise, and individual metabolism
• Normal, healthy glucose metabolism includes some rise after eating carbohydrates

If you’re metabolically healthy, your blood sugar should start around 70-90 before eating, spike to a max of 130 after eating, and then go back down to normal range 70-90 within two hours after eating. 

Optimal Blood Sugar Targets 

Current functional medicine guidelines suggest the following optimal ranges:

• Fasting blood glucose: 70-90 mg/dL
• Post-meal peaks: Ideally below 130 mg/dL
• Hemoglobin A1C: Below 5.0 (with 4.5-4.8 considered exceptional)

These targets are more stringent than conventional medical guidelines, which typically consider readings below 100 mg/dL for fasting glucose and A1C below 5.7 as normal.

Research-backed approaches to improve glucose regulation include:

• Post-meal movement: Even a 10-15 minute walk can significantly reduce glucose spikes
• Meal sequencing: Consuming fiber, protein, and fat before carbohydrates
• Stress management: Cortisol elevation directly increases blood glucose
• Sleep optimization: Poor sleep reduces insulin sensitivity by 25-30%
• Strategic supplementation: Compounds like berberine have demonstrated glucose-regulating effects
• Meal spacing: Allowing 3-4 hours between meals supports metabolic flexibility

Sleep, Light Exposure, and Cortisol

When you look at how it was in the seventies and eighties, we didn’t have LED artificial lights, constant screen time, or the bright white overhead lighting that’s now common. We had amber lights that weren’t directly overhead. Modern environments packed with blue-enriched light from screens, LEDs, and overhead lighting significantly disrupt natural light-dark cycles that regulate hormone production – they suppress melatonin production (our sleep hormone) and disrupt cortisol rhythms (our stress hormone).

Healthy cortisol patterns follow a diurnal rhythm—highest in early morning (promoting wakefulness) and lowest at night when melatonin rises. Disruption of this pattern contributes to:

• Sleep disturbances
• Blood sugar dysregulation
• Increased inflammation
• Impaired cognitive function
• Accelerated aging

So exposure to these harmful lights, especially in the hours before bed, can really affect your circadian rhythm, your sleep, and your overall health. Some tips for preventing the negative effects of blue light: 

• Morning sunlight exposure: 10-30 minutes ideally within an hour of waking
• Blue-blocking glasses: Wearing amber lenses after sunset
• Lighting adjustments: Using warmer, dimmer lighting in evenings
• Caffeine timing: Delaying morning coffee until 90 minutes after waking
• Evening meal composition: Including moderate complex carbohydrates with protein and fat may support serotonin production and subsequent melatonin conversion
• Device boundaries: Keeping screens out of the bedroom and limiting evening use