What is a healthy fasting glucose level?

Clinical labs often consider 70–99 mg/dL normal for fasting glucose. Many metabolic health experts consider 72–85 mg/dL a tighter optimal range. Your clinician can help interpret your results in context.

What post-meal glucose peak is considered healthy?

A common clinical threshold is keeping post-meal glucose under 140 mg/dL. For tighter metabolic goals, many people aim for peaks under 110 mg/dL and a return toward baseline within about two hours.

How do refined carbohydrates affect blood sugar?

Refined carbohydrates digest quickly and can cause sharp glucose rises and insulin responses. Replacing them with whole-food carbohydrates, fiber, and adequate protein tends to smooth post-meal curves.

Does walking after meals help glucose?

Yes. Light movement after eating helps muscles take up glucose. Studies suggest even 10–15 minutes of walking soon after a meal can meaningfully blunt post-meal glucose rises for many people.

How to control your blood sugar and improve your metabolic health | Levels

01 — Foundation

Blood Sugar & Metabolic Health: What the Numbers Mean

Most people first learn about blood sugar from a fasting glucose test at their annual physical. That number is useful — but it captures a single snapshot. What actually matters for long-term health is your glucose pattern: how high you spike after meals, how quickly you return to baseline, and how much insulin your pancreas is producing to keep pace.

Metabolic health 101

When you eat carbohydrates, blood sugar rises. Your pancreas releases insulin to bring it back down. This is normal — but when it happens repeatedly and dramatically, two things go wrong. First, cells become less responsive to insulin's signal, a condition called insulin resistance. Second, the pancreas has to produce more and more insulin to get the same effect. Both chronically elevated glucose and chronically elevated insulin independently contribute to a long list of problems: Type 2 diabetes, cardiovascular disease, weight gain, cognitive decline, inflammation, and more.

The good news is that glucose control is highly responsive to lifestyle. The strategies in this guide address the root causes directly — and their effects can show up within days to weeks. What they look like in practice will be individual: the same meal affects different people very differently, which is why a continuous glucose monitor (CGM) is such a useful tool for personalization.

Key distinction

Standard lab tests — fasting glucose and HbA1c — are what most clinical guidelines are built around, and they're the right place to start. But they share a blind spot: they don't capture what happens between meals. A person can have a "normal" fasting glucose and still experience dramatic post-meal spikes that, over years, drive insulin resistance. The interventions below address all of these markers regardless of which tests you have access to.

Go deeper (audio)

Hear researchers explain glucose, insulin resistance, and metabolic testing in long-form on A Whole New Level, Levels' podcast hub.

Target ranges

Fasting glucose

Lab normal70–99 mg/dL

Optimal72–85 mg/dL

Post-meal peak

Acceptable<140 mg/dL

Optimal<110 mg/dL

HbA1c

Lab normal<5.7%

Optimal<5.4%

Fasting insulin

Lab normal<18 μIU/mL

Optimal<5 μIU/mL

02 — Core dietary strategies

Three Dietary Levers With the Strongest Evidence

Diet is where most people have the most direct control over blood sugar. These three strategies work through distinct biological pathways and their effects are additive. Individual responses vary — sometimes substantially — but the general direction of effect is well-supported.

Reduce Refined Carbs & Added Sugar

The goal isn't to avoid all carbs — it's to cut the ones doing the damage

Targets

0g added sugar (optimal)|<50g net carbs/day (interventional) · <100g (maintenance)

Why it works

Refined carbohydrates — white flour, sugar, processed grains — are stripped of the fiber, vitamins, and minerals that slow digestion. Without fiber to buffer them, they enter the bloodstream rapidly, causing sharp blood sugar spikes and the insulin surges that follow. Repeated over time, this drives insulin resistance. Added sugars are particularly potent: each additional daily serving of sugar-sweetened beverages has been linked to a 27% higher risk of Type 2 diabetes over the long term. The core move is straightforward — cut refined carbs and added sugars first, and let whole-food carbohydrates and fiber do their job.

↳ On net carbs

Net carbs = total carbs minus fiber. Fiber doesn't raise blood sugar — it slows glucose absorption. This is why black beans (high total carbs, very high fiber) respond very differently from white rice (similar total carbs, almost no fiber). Tracking net carbs gives a more accurate picture of what's actually driving your glucose response than total carbs alone.

↳ Interventional vs. maintenance

Interventional (<50g net carbs/day): For people actively working to improve insulin sensitivity or lower fasting glucose — a meaningful step down from the average American intake of 200–300g/day. Maintenance (<100g/day): Once glucose control is established, this less restrictive approach still dramatically outperforms a standard Western diet. The right level depends on your baseline and goals.

Think in three tiers

Rather than counting every gram, think about carbohydrates by how often to eat them:

Eat freely

Non-starchy vegetables (spinach, broccoli, cauliflower, zucchini, peppers) and low-sugar fruits (berries, kiwi, grapefruit)

In moderation

Starchy vegetables (sweet potatoes, beans, lentils), higher-sugar fruits (apples, bananas), and whole grains (oats, quinoa, brown rice)

Minimize/avoid

Sodas, juices, sweeteners, white bread, crackers, flour-based products, and highly processed foods

Key actions

Cut added sugars first — sweetened beverages, desserts, flavored yogurts, sauces, and packaged snacks are the highest-impact targets

Read labels for hidden sugars: at least 61 different names appear, including maltose, dextrose, brown rice syrup, cane juice, and agave

"Natural" sugars — honey, agave, brown sugar — are not healthier; your body processes them the same way as white sugar

Save any higher-carb whole foods for after exercise, when muscles are primed to absorb glucose efficiently

Smart swaps

Higher-glycemic choice		Better alternative
Soda (39g sugar / 12 oz)	→	Sparkling water with lemon (0g sugar)
Orange juice (26g sugar / 8 oz)	→	Whole orange (9g sugar + 3g fiber)
Pasta (43g net carbs/cup)	→	Zucchini noodles (3g) or lentil pasta (23g + 7g fiber)
White rice (45g net carbs/cup)	→	Cauliflower rice (2g) or cooked-and-cooled rice (lower GI)
Sandwich bread (24g net carbs)	→	Lettuce wrap (1g) or whole grain slice with protein and fat

Prioritize Protein at Every Meal

Stabilizes blood sugar through multiple mechanisms

Targets

25–35g protein per meal|1.2–1.6g per kg body weight daily

Why it works

Protein has minimal direct impact on blood sugar while actively helping stabilize glucose when eaten alongside carbohydrates — it slows digestion and blunts the rate of glucose absorption. Protein also supports muscle mass, and muscle tissue acts like a glucose sponge, pulling sugar from the bloodstream both with and without insulin. More muscle means better glucose disposal and improved insulin sensitivity over time.

↳ Individual variation

Protein needs vary by age, activity level, and body composition goals. Older adults (65+) need more to prevent muscle loss; athletes and those doing heavy resistance training may need up to 2.0–2.2g/kg. Very high protein intake can be converted to glucose via gluconeogenesis in some circumstances — find your optimal amount rather than maximizing without limit.

Key actions

Target 25–35g protein per meal — roughly a palm-sized portion of meat, fish, or equivalent

Eat protein before carbs at meals — this order has been shown to meaningfully reduce post-meal glucose spikes

Include protein with every snack to buffer any carbohydrates you're eating alongside

Choose high-quality sources: lean meats, fish, eggs, Greek yogurt (unsweetened), cottage cheese, legumes

Smart swaps

Low-protein choice		Protein-forward alternative
Sugary cereal (1g protein, 30g net carbs)	→	Greek yogurt with berries (20g protein, 8g net carbs)
Bagel (10g protein, 50g net carbs)	→	Scrambled eggs with avocado (25g protein, 4g net carbs)
Crackers as a snack (2g protein)	→	Almonds with cheese (12g protein)

Increase Fiber Intake

Slows glucose absorption, feeds your gut microbiome, and keeps you full — most Americans get less than half the optimal amount

Targets

35–50g total fiber/day|increase gradually over 1–2 weeks

Why it works

Fiber is a carbohydrate that your body largely can't digest — so it doesn't raise blood sugar the way other carbs do. Soluble fiber forms a gel in the digestive tract that slows gastric emptying and blunts post-meal glucose spikes. Insoluble fiber speeds food through the gut and has been linked to lower insulin resistance. Both types feed the gut microbiome, which ferments fiber into short-chain fatty acids — particularly butyrate — that improve insulin sensitivity and reduce inflammation. One large meta-analysis found that every additional 10g of daily fiber reduced the risk of Type 2 diabetes by 25%. The US average fiber intake is around 12–14g per day; Levels advisors recommend 35–50g.

↳ Individual variation

Increasing fiber too quickly can cause gas and bloating. Add 5g per week until you reach your target. People with IBS or other GI conditions should work with a practitioner, as some high-fiber prebiotic foods are also FODMAPs.

Key actions

Build meals around high-fiber foods: vegetables, legumes, berries, chia seeds, flaxseeds, avocado

Consider psyllium husk (5–10g/day with meals) — the most consistently studied fiber supplement for blood sugar and cholesterol reduction

Include fiber with any carbohydrate-containing meal — even adding a handful of non-starchy vegetables meaningfully buffers the glucose response

Prioritize whole-food fiber over supplements — fibrous foods also contain polyphenols, antioxidants, and micronutrients that amplify the benefit

Try cooked-and-cooled starches (rice, potatoes, lentils) — cooling converts some starch to resistant starch, which acts like fiber in the gut

High-fiber foods for glucose control

Food		Fiber per serving
Chia seeds (2 tbsp)		11g fiber, 2g net carbs
Black beans (1 cup cooked)		15g fiber
Avocado (½ large)		7g fiber, low glucose impact
Lentils (½ cup cooked)		8g fiber
Raspberries (1 cup)		8g fiber, low glucose impact
Ground flaxseed (2 tbsp)		4g fiber, minimal net carbs

03 — Supporting strategies

Exercise, Sleep & Stress

Exercise and sleep have meaningful evidence for glucose control — each working through mechanisms the dietary strategies don't fully address, and likely amplifying their effects.

Exercise: Post-Meal Walks + Resistance Training, Combined

Two types of movement work through distinct mechanisms — combining them produces better outcomes than either alone

Targets

10–15 min post-meal walks|150+ min/week Zone 2|2–3× resistance training/week

Why it works

When muscles contract, they pull glucose from the bloodstream without requiring insulin, creating immediate blood sugar lowering effects lasting 24–72 hours after exercise. Regular training also increases the number of glucose transporters in muscle cells and builds more muscle mass overall, compounding long-term improvements in glucose control. In one study, ~170 minutes of weekly exercise improved insulin sensitivity by approximately 85% in overweight sedentary adults. The landmark Diabetes Prevention Program found that lifestyle intervention including regular physical activity reduced new diabetes incidence by 58% in people with prediabetes.

↳ Individual variation

High-intensity exercise may temporarily raise glucose, but these spikes are not concerning. Benefits typically compound over 8–12 weeks of consistent training.

Key actions

Post-meal walks: 10–15 minutes within 30 minutes of eating can reduce glucose spikes by 20–30% — the highest-leverage single habit in this guide

If currently sedentary, start with 20–30 min walks 3–4× per week — building the habit matters more than optimizing intensity early

Add resistance training 2–3× per week: squats, rows, push-ups, and deadlifts; 30–45 min per session, targeting major muscle groups

Zone 2 cardio (can hold a conversation but not sing comfortably): brisk walking, cycling, swimming, or rowing for 150+ min/week

Break up extended sitting with 2-minute movement breaks — even brief muscle contractions help with glucose clearance throughout the day

Weekly targets

Type

Target

Example activities

Post-meal walks

10–15 min daily

Any easy walking pace within 30 min of eating

Zone 2 cardio

150+ min/week

Brisk walking, cycling, swimming, rowing — can hold a conversation

Resistance training

2–3 sessions/week

Full-body compound movements; squats, rows, push-ups; 30–45 min

Sleep & Stress: Supporting Infrastructure

Poor sleep and chronic stress don't show up on a glucose test — but they undermine everything else you're doing

Targets

7–9 hours nightly|15 min/day mindfulness or breathwork

Why it works

Short sleep and elevated cortisol from chronic stress both disrupt insulin sensitivity through distinct mechanisms. Cortisol directly triggers glucose production in the liver and reduces cellular glucose uptake — independently of what you eat. Even a single night under 6 hours has measurable effects on next-day glucose response. The effects compound: poor sleep raises cortisol, and elevated cortisol worsens sleep quality.

Key actions

7–9 hours of sleep nightly — under 6 hours measurably worsens glucose control the following day

Consistent sleep/wake times, including weekends — circadian stability matters as much as total hours

Cool, dark room: 65–68°F (18–20°C); no screens 30–60 min before bed

Avoid large meals within 3 hours of bed — late eating drives overnight glucose elevation

10–15 min daily breathwork or meditation — consistent evidence for cortisol reduction and improved insulin sensitivity

Limit alcohol — even moderate amounts impair sleep quality and directly affect next-day glucose

↑ Additional factor worth considering

A 14–16 hour overnight fasting window (e.g., dinner at 7 PM, breakfast at 9 AM) may improve insulin sensitivity and help the liver clear glucose more efficiently overnight — though individual responses vary. Start with a 12-hour window and extend gradually.

04 — Continuous glucose monitoring

Personalize What Works for You

The strategies above are population-level guidelines. A CGM is how you personalize them — seeing exactly how your body responds to food, exercise, and sleep in real time.

📡

A real-time window into your metabolic health

A small sensor worn on the arm, replaced every 10–14 days

A CGM is a wearable sensor — about the diameter of a quarter — that measures your glucose every few minutes and sends the data to your smartphone. A tiny filament sits just beneath the skin and converts glucose into an electrical signal that's transmitted to an app like Levels. You can shower, sleep, swim, and exercise while wearing it.

What makes a CGM powerful for people without diabetes isn't the moment-to-moment number — it's the patterns over time. Even if you eat the same meal as someone else, your glucose response will be individual to you. A CGM reveals this bio-individuality, letting you optimize based on actual data rather than population averages.

Levels target ranges (people without diabetes)

Fasting glucose

72–85 mg/dL

24-hr mean glucose

79–100 mg/dL

Post-meal peak

<110 mg/dL

<30 mg/dL rise from pre-meal baseline

Time in range

>90% at 70–110 mg/dL

What you learn from wearing one

Why you feel the way you feel. Many people's first CGM insight is discovering how directly their energy, mood, focus, and cravings track with their glucose curve — the mid-afternoon slump after a high-carb lunch, the brain fog that follows a spike-and-crash, the surprising steadiness after a protein-forward meal. This connection is one of the most commonly reported revelations among new CGM users, and it's the one that makes the behavior changes feel worth it.

Which specific foods spike your glucose — often surprising ones like oatmeal, fruit smoothies, and rice cakes that are commonly considered "healthy"

How much post-meal walks actually reduce your individual glucose response — and whether timing or duration matters more for you

How a single night of poor sleep affects your glucose the next day — and whether stress alone is elevating your levels independently of diet

Your "glucose stacking" opportunities: combining multiple interventions (protein first + post-meal walk + fiber) with a typically problematic food to see if you can minimize its impact

Levels members can order a CGM directly through the member portal. Many people find 2–4 weeks of wear every 3–6 months sufficient to maintain and refine the insights they've built — continuous wear is not required. Learn more about getting a CGM →

Podcast deep dives

Video thumbnail: Dr. Robert Lustig on blood sugar, CGMs, and metabolic flexibility

A Whole New Level

The science of blood sugar — CGMs, metabolic flexibility, and what your glucose data actually tells you

Dr. Robert Lustig — Professor, UCSF

A Whole New Level

Insulin resistance, muscle as a metabolic organ, and why protein intake matters more than most people realize

Dr. Ben Bikman — Professor, Brigham Young University

Join Levels to get a Glucose Control program that helps you adopt and stick to these habits, alongside blood testing and CGMs to see your improvement over time.

Get started →

How to control your blood sugar and improve your metabolic health

Blood Sugar & Metabolic Health: What the Numbers Mean

Three Dietary Levers With the Strongest Evidence

Reduce Refined Carbs & Added Sugar

Prioritize Protein at Every Meal

Increase Fiber Intake

Exercise, Sleep & Stress

Exercise: Post-Meal Walks + Resistance Training, Combined

Sleep & Stress: Supporting Infrastructure

Personalize What Works for You

A real-time window into your metabolic health

How to get a CGM without diabetes — and what you can learn

The 2026 Levels Guide to continuous glucose monitoring

Why you should reduce sugar and refined carbs — and the smart way to do it

What should my glucose levels be? The complete guide

What is a blood sugar spike — and why does it matter?

Walking after a meal: the research on post-meal exercise and blood sugar