Blood Sugar 101: What to Eat for Energy, Cravings & Focus

When people talk about “balancing blood sugar,” it can sound like something only diabetics need to worry about. But here’s the truth: if you’re dealing with low energy, brain fog, afternoon crashes, mood swings, or intense cravings—your blood sugar is likely involved.

As a functional nutritionist, I see it all the time: clients eating “healthy” but still struggling to feel focused, energized, and emotionally balanced throughout the day. Why? Because their glucose and insulin balance is off—and that impacts everything from your metabolism to your mental clarity.

First, What Is Blood Sugar Balance?

Blood sugar balance means keeping your blood glucose levels steady—not too high or too low. This balance is key for sustained energy and overall health.

Why Blood Sugar Balance is Important

Keeping your blood sugar levels steady is one of the most important things you can do for your overall health. Here’s why it matters:

• It fuels your body and brain. Glucose is your body’s main source of energy—especially for your brain. When levels are stable, you feel more energized, focused, and clear-headed.
• It helps prevent chronic disease. Frequent spikes and crashes in blood sugar can, over time, contribute to serious health issues like heart disease, kidney damage, and nerve problems. Let’s not forget about insulin resistance as well.
• It supports your mood and mental health. Since the brain needs glucose, blood sugar swings can affect how you feel mentally and emotionally. Stable levels are linked to better mood, less anxiety, and improved concentration.

Maintaining balanced blood sugar isn’t just about avoiding sugar—it’s about eating the right foods, at the right times, to keep your body and mind functioning at their best.

Here’s What Happens After You Eat

After you eat, your blood sugar (glucose) levels naturally rise. In response, your pancreas releases insulin, a hormone that helps move glucose into your cells to be used for energy. Any extra glucose gets stored in your liver as glycogen.

As your blood sugar starts to dip in the hours after eating, your liver steps in and releases some of its stored glucose to keep levels steady. This natural balance happens between meals and helps maintain your energy and focus throughout the day.

But when you eat more glucose than your body needs—and your liver and muscle glycogen stores are full—your body converts the excess into fat (including visceral fat) for long-term energy storage.

When you go without food for over 18 hours (fasting), your body uses up the stored glucose in your liver for energy. Once those stores run low, your body begins breaking down fat from fat cells. These fats travel to the liver, where they’re converted into ketones—an alternative fuel source your body can use when glucose isn’t available. This metabolic shift is known as ketosis, where fat becomes the preferred fuel source, due to lack of glucose.

Remember, that mastering metabolism requires ATP—the body’s energy currency— which is produced from glucose and powers many vital functions. This includes active transport across cell membranes, muscle contraction, hormone and cell membrane synthesis, nerve signal transmission, cell growth and division, and other essential physiological processes.

Organs Involved in Balancing Blood Sugar

After you eat, your GI tract breaks down and absorbs nutrients—mostly in the small intestine. From there, several organs work together to maintain glucose homeostasis, or stable blood sugar levels.

Pancreas

The pancreas plays a key role in blood sugar regulation. After a meal, it releases insulin to help lower blood glucose by moving sugar into your cells. When blood sugar is low—like between meals or during fasting such as sleeping—it releases glucagon, which signals the liver to release stored glucose.

In type 2 diabetes, either the pancreas doesn’t make enough insulin, or the body becomes insulin resistant, meaning it doesn’t respond properly to insulin.

The function of the pancreas is also influenced by the nervous system, which helps regulate hormonal responses based on your body’s energy needs.

Liver

The liver (and muscles) stores glucose for later use as glycogen and, when needed, helps produce and release glucose through processes called gluconeogenesis and glycogenolysis. These functions are also regulated by the nervous system. If the liver is damaged or not functioning properly, maintaining healthy blood sugar levels becomes much more difficult.

Kidneys

The kidneys act as the body’s filtration system—removing waste from the blood and returning clean blood to circulation. They also help regulate fluid balance, blood pressure, and bone health, and produce hormones needed to make red blood cells. An often-overlooked role: kidneys help clear insulin from the bloodstream, playing a key role in blood sugar regulation.

During stress or fasting, the kidneys can even produce glucose from non-carbohydrate sources (a process called gluconeogenesis) and use glucose for their own energy needs. When the kidneys aren’t functioning properly, both their filtration ability and glucose metabolism can be impaired, leading to insulin resistance.

The Brain and Nervous System

The hypothalamus and brainstem are key parts of the brain (and nervous system) that help regulate your blood sugar and energy levels. They constantly monitor how much glucose is in your blood and send signals to your body—like when you’re hungry or full.

Inside the hypothalamus, certain areas respond to hormones such as insulin, leptin, and ghrelin. These hormones come from your gut and fat tissue and tell your brain whether you need more energy (food) or if you’re satisfied. This system helps control your appetite and how your body uses energy.

But when these hormones get out of balance—or when your body stops responding to them properly, like with leptin or ghrelin—you may feel overly hungry or not hungry at all. This can lead to problems like overeating, low energy, poor blood sugar control, and even mental health issues like anxiety or mood swings.

This communication between your gut and brain is known as the gut-brain axis. It depends on hormones—like leptin and ghrelin—which bind to receptors in your brain and nervous system to help control hunger, metabolism, and overall energy balance.

Bottom Line

Too much glucose too quickly or frequently? Too much glucose—especially too quickly or too often—can cause a spike, then a crash, leaving you tired, jittery, or anxious. Once glycogen stores are full, your body stores the excess glucose as fat for long-term energy.
Too little? Your energy drops, your cravings spike, and your brain feels like it’s in a fog.

This rollercoaster is what leads to:

• Energy crashes after meals
• Mood swings or irritability (aka “hangry”)
• Sugar or carb cravings
• Trouble focusing
• Poor workout recovery or performance

Blood Sugar and the Brain: Why Focus & Mood Depend on Glucose Stability

Your brain is a high-energy organ that runs primarily on glucose. It needs about 120 grams of glucose per day just to function properly! When your blood sugar spikes and crashes, it doesn’t just affect your body—it affects your mood, memory, motivation, and focus too.

Keeping your blood sugar stable means more calm, steady energy and clearer thinking throughout the day.

And remember, when glucose runs low—like during long fasting or starvation—your body switches gears and starts making ketones, a backup fuel source that helps keep your brain and vital organs running strong.

So What Do You Eat (and When) to Balance Blood Sugar?

Your body’s ability to handle glucose changes throughout the day, following your circadian rhythm (your internal body clock). In the morning, your body is best at processing glucose—this is when your metabolism and insulin response are strongest. By the afternoon and evening, your ability to manage blood sugar (called glucose tolerance) starts to dip.

That’s because the pancreas, which releases insulin, works most efficiently earlier in the day. Later in the day, your fat cells become more sensitive to insulin, and your body shifts toward storing rather than using energy. This natural rhythm is why when you eat can be just as important as what you eat.

Here are practical tips to begin balancing your blood sugar.

Every meal should include:

• Protein (like eggs, fish, chicken, legumes): slows glucose absorption
• Healthy fats (avocado, nuts, olive oil): supports hormone balance and satiety
• Fiber-rich carbs (leafy greens, berries, sweet potato): stabilize energy
• Whole, unprocessed foods: reduce inflammation and insulin spikes

Timing Tips:

• Eat within 90 minutes of waking to anchor blood sugar early
• Don’t skip meals—it increases cortisol and makes crashes worse
• Pair carbs with protein/fat to reduce spikes
• Eat more carbs around movement, when your body is primed to use them. Pro tip: eat the majority of your carbs during the day rather than at night (before bed).

Functional Nutrition’s Goal: Blood Sugar Flexibility, Not Fear

This isn’t about cutting carbs or fearing food—it’s about eating in a way that supports your body’s natural energy rhythms. When your blood sugar stays steady, everything gets better: mood, cravings, focus, sleep, and even hormone balance.

Your body is designed to switch between using glucose and fat for energy—this is called metabolic flexibility, and it’s key for avoiding those energy crashes and keeping blood sugar stable.

Ready to Support your Metabolism and Feel More like Yourself?

Curious about your current health status? Ask us about our Longevity Lab Panels. At Tucson Wellness MD, we test—we don’t guess. Schedule your visit today! Don’t forget to follow along on Instagram this week for a full day of blood-sugar-balanced meals, smart snack swaps, carb timing strategies, and real-life tips to help you feel your best—without restriction.

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