Most old-school metabolism talk centers around weight—whether a metabolism is “fast” or “slow,” or how to “boost” it. This conversation always seems to come back to how a body looks. But there’s much (much!) more to metabolism than that.

At its core, metabolism is the way your body turns food into fuel and uses that energy to keep you functioning. “This includes how efficiently cells generate energy, how hormones regulate fuel use, and how stable those systems remain throughout the day,” explains Sunjya Schweig, M.D., integrative family physician and founder at California Center for Functional Medicine. “These processes affect not only body composition, but also brain function, mood, and resilience.”

If you’ve ever experienced the dreaded midday slump, felt shaky and irritable, or gotten into bed somehow exhausted and wired at the same time, your metabolism could have something to do with it. This doesn’t mean every cranky afternoon or low-energy stretch is a metabolism problem—and supporting your metabolic health isn’t a stand-in for mental health care. However, the way your body makes, uses, and regulates energy has a real impact on how you feel day to day.

Ahead, experts explain how metabolism and mood are connected, the subtle signs your metabolic health may be affecting how you feel, and the realistic ways to support steadier emotions and energy from the inside out. 

• ABOUT OUR EXPERTs: Sunjya Schweig, M.D., is an integrative family physician and founder at California Center for Functional Medicine. Megan Meyer, Ph.D., is a science communications consultant. Kiera Lane, N.M.D., MSAc, L.Ac., Dipl. Ac., is a naturopath and the director of Arizona Natural Medicine.

The Link Between Metabolism And Mood

Your mood reflects your metabolic function in a few different ways. For starters, your brain is a very high-maintenance organ, meaning it needs a steady supply of energy to help you focus, regulate emotions, make decisions, and allow you to generally feel like a functioning human, according to science communications consultant Megan Meyer, Ph.D.

When that energy supply is stable, you’re more likely to feel like yourself. When it’s not, cue the brain fog, irritability, and “why am I suddenly exhausted?” spiral.

“The brain depends on a steady supply of energy, and fluctuations in that supply can directly affect how we feel,” agrees Schweig. “When blood sugar levels rise and fall rapidly, the brain experiences that as instability, which can lead to mood swings, irritability or low energy.” In fact, drops in blood sugar trigger the release of stress hormones like cortisol and adrenaline to bring levels back up. The result? You might feel anxious, jittery, snappy, or suddenly wiped out, Schweig explains.

Read More: Chronically Busy? Here’s How That Effects Your Body 

Sleep struggles, stress, and inflammation all also contribute to metabolic dysfunction that impacts your mood and energy. Poor sleep makes it harder for your body to regulate blood sugar, chronic stress keeps cortisol elevated (which can throw off energy levels, cravings, and mood), and experts increasingly recognize inflammation as part of the mental health equation.

Many of these factors influence cellular health, which is ultimately central to metabolic health. When the mitochondria, which are responsible for producing ATP, the cells’ energy currency, don’t function well, low energy, brain fog, poor focus, and that “dragged down” feeling are hard to shake, adds naturopath Kiera Lane, N.M.D., MSAc, L.Ac., Dipl. Ac., director of Arizona Natural Medicine.

Signs Your Metabolism Might Be Contributing to a Cranky Mood

Of course, a million culprits could be behind you feeling foggy, cranky, or tired: You could be under-slept, overbooked, dehydrated, PMS-ing, emotionally drained, coming down with something or just having a wildly human day. That said, experts say there are a few patterns that may point to a metabolic issue.

1. You crash hard in the late morning or afternoon

If you feel decent after eating and then completely tank a couple of hours later, it may be a sign that your blood sugar isn’t staying as steady as it should be, according to Schweig. Noticeable energy crashes (often in the late morning or afternoon) are a telltale sign that your metabolic health needs some attention.

2. You crave sugar or refined carbs later in the day

Cravings—especially ones that hit in the afternoon or evening—can also indicate that metabolic instability is affecting your wellbeing. “These are signals that the brain is not getting stable fuel,” says Meyer. (Some folks might also find themselves craving caffeine in these moments, according to Schweig.)

3. You get shaky or irritable between meals

If skipping or delaying a meal makes you feel snappy, jittery, anxious, or like you suddenly cannot function like a normal person, blood sugar may be part of the picture, warns Schweig. Feeling like you can’t get through your next task without grabbing something to eat is another giveaway. 

4. Your sleep is Way Off

Sleep and metabolic health are closely linked, and a disruption to one often leads to disruption in the other. So, if you often wake up in the middle of the night, feel wired but tired at bedtime, or need a lot of caffeine to function during the day, your metabolism could be asking for help, the experts say. 

How To Support Your Metabolism And Fix Your Cranky Mood

For many people, stabilizing blood sugar and energy can make a real difference in how they feel mentally. Remember, your brain likes consistency! Stability here means fewer surges of stress hormones and a consistent feed of much-needed fuel that allow you to feel balanced and alert throughout the day, according to Schweig. 

And, nope, you don’t need to obsess over every bite or monitor your glucose like it’s your job. These simple, effective strategies will set you up for smoother sailing.

1. Don’t Eat “Naked” Carbs

News flash: Carbs aren’t the enemy. Your brain and body need them for energy, and foods like fruit, oats, potatoes, and rice can absolutely have a place in a healthy diet. Meanwhile, fast-digesting carbs—think white toast, pastries, crackers, pretzels, sugary granola bars, or sweetened coffee drinks—can hit your system quickly (especially when eaten on their own), which may leave you foggy, snacky, irritable, or weirdly desperate for more sugar an hour later, Schweig explains.

Read More: 5 Low-Calorie Ways To Increase Your Protein

The fix here is refreshingly simple: When eating carbs (especially those quick-digesting ones!), pair them with something that slows digestion way down. Protein, healthy fat, and fiber are your best friends here, as each supports balanced digestion and blood sugar, Meyer says. Start by pairing your carbs with plenty of protein (aim for 20 to 25 grams for meals and about 10 grams for snacks), add fiber in the form of vegetables, seeds, or beans, and incorporate healthy fats from avocado, olive oil, or nuts, she suggests.

2. Move your body most days

High-intensity workouts are great for building strength, boosting heart health, and getting that endorphin rush, but you don’t have to go all-out every day to support your metabolism. You do, however, still need to get moving.

Thankfully, research shows that even a 20- to 30-minute walk after a meal can reduce post-meal blood sugar spikes. Seems like a pretty doable place to start, right?

That said, strength training is another must-do here. “Strength training helps improve insulin sensitivity, meaning your body handles blood sugar more efficiently, leading to more stable energy and fewer crashes,” Lane explains. The Physical Activity Guidelines for Amereicans suggest adults do at least two days of strength exercises per week. 

3. Get serious about sleep 

We all know sleep is important, but it also tends to be one of the first things to fall by the wayside when life gets busy.

Unfortunately, your metabolism notices. Research suggests that skimping on sleep can make it harder for your body to regulate blood sugar, throw hunger and stress hormones out of whack, and leave you feeling a whole lot more emotionally reactive the next day.  “Even one night of bad sleep can reduce your ability to handle stress and make cravings for sugar and caffeine worse,” says Lane.

A few boring-but-effective sleep moves she recommends: Keep your room cool and dark, limit alcohol close to bedtime, avoid huge meals right before bed, and create some kind of wind-down routine that tells your body the day is actually ending (even if it’s just five minutes long!). If you’re coming off a rough night, experts recommend leaning into protein, hydrating like it’s your job, avoiding stimulants as much as possible, and getting outside. 

4. Manage stress like it actually affects your body (because it does)

Stress isn’t just a mental thing. Your body feels it, too. When the stress hormone cortisol stays high for too long, it can mess with blood sugar, increase cravings, interfere with sleep, and leave you feeling anxious, foggy, or totally fried, explains Schweig. In other words, chronic stress is a disaster for your metabolic function.

No, we’re not about to tell you to eliminate all stress from your life (because let’s be real…), but quick and simple supports can go a long way. A few minutes of deep breathing, a walk outside, taking an actual lunch break, getting morning light, stepping away from your screen between meetings, stretching before bed, and saying “no” when you need to can all make a big difference, according to Lane. 

“When stress is better managed, people often notice fewer mood swings, improved focus and a greater sense of calm,” she says. “It’s not about eliminating stress, but about building resilience so your body doesn’t stay stuck in a constant ‘fight or flight’ state.”

SupplemenT Smart

If your metabolism is messing with your mood, supplements can be genuinely helpful; just don’t expect them to do all the heavy lifting. “They work best when the basics—food, movement, sleep and stress management—are already getting at least some attention,” says Schweig. Here are a few experts recommend for supporting a healthier metabolism and more balanced mood.

1. Berberine

Berberine has earned itself a very 2026 nickname online: “nature’s GLP-1.” Experts say the comparison is a little oversimplified, but not totally random.

To be clear, berberine doesn’t work the same way prescription GLP-1 medications do, but it has been studied for its potential effects on metabolic health, especially blood sugar regulation. In one 2022 review published in Frontiers in Pharmacology, researchers looked at 37 clinical trials involving more than 3,000 people with type 2 diabetes and found that berberine was linked to improvements in key blood sugar markers, including fasting glucose, HbA1c, and post-meal glucose. 

“Berberine is one of the most well-studied natural compounds for metabolic health,” says Schweig. “It helps regulate blood sugar and improve insulin sensitivity—essentially helping your body move glucose into cells more efficiently.”

That said, berberine is not something to casually throw into your cart, as it can interact with certain medications, including those for blood sugar and blood pressure, and may cause digestive side effects, warns Schweig. Have a conversation with your healthcare provider before giving it a go.

2. Magnesium

Magnesium wears a lot of hats, which is why it comes up in conversations about sleep, stress, muscle recovery, blood sugar, and mood.

From a metabolic standpoint, magnesium plays a role in how your body uses glucose and responds to insulin, according to Schweig. This matters because insulin is what helps move glucose out of your bloodstream and into your cells for energy. In fact, low magnesium levels have been associated with insulin resistance and increased stress reactivity.

Magnesium also helps support a calmer stress response, which is a big deal when you remember that chronic stress and elevated cortisol can mess with blood sugar, cravings, sleep, and mood. 

Magnesium might not magically fix your metabolism or turn you into the most regulated person alive overnight, but it can be a supportive player, especially if you’re not getting enough of it. Magnesium glycinate is often a go-to for folks concerned about stress.

3. Omega-3s

Omega-3s may not be the first thing people think of when they hear “metabolic health,” but they absolutely belong in the conversation.

EPA and DHA (the omega-3s found in fatty fish and fish oil) help support healthy cell membranes, play a role in a healthy inflammatory balance, and have been shown to support healthier triglyceride levels, explains Lane. They’re also important for brain health.

Because of all of these factors, omega-3s may help create a better internal environment for mood, focus and cognitive function, Lane suggests. In fact, research has also linked omega-3 supplementation (especially EPA-heavy formulas) with improvements in low mood.

Your first move here is to eat fatty fish—like salmon, sardines, anchovies, or trout—a couple of times per week, she says. If that’s not happening, ask your healthcare provider about an omega-3 supplement.

4. B vitamins

B vitamins help your body turn the food you eat into usable fuel,  which makes them very relevant when we’re talking about metabolism (and particularly fatigue), explains Meyer.

A B-complex isn’t going to magically fix your mood or metabolism overnight, but it can be helpful if you’re not getting enough from food or have a harder time absorbing nutrients. “That can be more common with age, certain digestive issues or medications, and for people following vegetarian or vegan diets,” Meyer notes.

There’s also some research suggesting B-vitamin supplementation may support mood, though the biggest benefit is likely in people who actually need more of them.

Start by increasing your intake of B-rich foods like eggs, dairy, meat, fish, poultry, legumes, and leafy greens. If you suspect you’re falling short (or dealing with pesky symptoms that won’t quit), consider whether a B-complex makes sense for you.

5. NAD+

NAD+ sounds like something you’d hear about on a very intense longevity podcast, but it’s essential for making energy. Your cells need NAD+ to help make ATP (the energy your body runs on). It also plays a role in mitochondrial function, metabolic regulation and cellular repair.

The tricky part is that NAD+ levels naturally decline with age and stress, which is why there’s so much interest in NAD+ precursors like nicotinamide riboside (or NR) and NMN, explains Meyer. “These compounds are used to help the body make more NAD+,” she says. 

Since NAD+ is so tied to cellular energy, it may also matter for metabolic health. Some research suggests NAD+ precursors like NMN may support insulin sensitivity. Research on NR for fatigue and cognitive function is still early and mixed but promising, per Schweig.

As for mood, these aren’t stimulants or “happy pills,” but if your cells are making energy more efficiently, you may notice more mental clarity, steadier focus, and less of that dragging-yourself-through-the-day feeling.

The Bottom Line

In some cases, a mysterious cranky mood or overall lack of energy could be your body struggling to regulate blood sugar or produce energy consistently. If you’re prone to irritability, exhaustion, cravings, or trouble focusing, make sure your lifestyle supports healthy metabolic function. Factors like consuming balanced meals, exercising regularly, and getting enough sleep set your body up for metabolic success—and a sunnier, clearer disposition.