Carbohydrates

Carbohydrates are your body’s preferred fuel for high-intensity work — your muscles and brain run on glucose. But not all carbs behave the same way once you eat them. Glucose, fructose, and fiber take completely different metabolic paths, and the speed at which carbs hit your bloodstream determines whether they fuel you or store as fat.

The klatiPRO protocol uses carbs strategically: enough to fuel training and recovery, timed to match activity, and sourced from foods that don’t spike insulin unnecessarily.

Key takeaways

• Not all carbs are the same — glucose fuels all cells, fructose goes straight to the liver, fiber feeds gut bacteria; they follow completely different metabolic paths
• Your body stores carbs as glycogen — muscles hold ~400g and liver holds ~100g; once full, excess glucose converts to fat; glycogen is the primary fuel for high-intensity training
• Glycemic load matters more than glycemic index — how much carb per serving, plus what else is in the meal, determines the actual blood sugar response
• Fructose is fine from whole fruit, potentially harmful in excess — the liver handles roughly 15–25g/day from whole fruit without problems in most healthy adults; above about 50g/day from added sugars, fructose metabolism resembles alcohol metabolism and is associated with fatty liver
• Cook starch, then cool it — retrograding creates resistant starch (RS3) that acts like fiber; feeds gut bacteria and produces butyrate
• Front-load your carbs — insulin sensitivity tends to be highest in the morning and after exercise; post-workout carbs refill glycogen more efficiently
• 25–29g fiber per day — this intake range is associated with the best cardiovascular and gut outcomes in large meta-analyses of generally healthy adults; increase gradually with adequate water
• Rinse your rice — inorganic arsenic in rice is a real concern; basmati tends to be lower risk; rinsing and cooking in excess water removes roughly 40–60% of arsenic content

Types of carbohydrates

Simple sugars (monosaccharides and disaccharides)

The smallest carbohydrate units — they absorb fast and hit the bloodstream quickly.

Glucose — the universal fuel. Every cell in your body can use it. Absorbed via the SGLT1 transporter in the jejunum (active transport — fast). Triggers insulin release, which shuttles glucose into muscle and fat cells.

Fructose — found in fruit, honey, and added sugars. Unlike glucose, fructose can only be processed by the liver. It enters via the GLUT5 transporter (passive — slower, limited capacity). At moderate doses from whole fruit, the liver handles it fine. At high doses, it overwhelms the liver — more on this below.

Sucrose — table sugar. One glucose + one fructose molecule bonded together. Your gut splits them apart, then each follows its own path.

Lactose — milk sugar. One glucose + one galactose. Requires the enzyme lactase to split. People who produce less lactase experience bloating and discomfort — this is lactose intolerance, not an allergy.

Complex carbs (polysaccharides)

Long chains of glucose molecules. They take longer to break down, which means slower absorption and a more controlled blood sugar response.

Starch — the storage form of glucose in plants. Found in: potatoes, rice, oats, bread, pasta, corn. Broken down by amylase (which starts in the mouth) into maltose, then into glucose.

Glycogen — the storage form of glucose in animals. Your muscles and liver store glycogen for quick energy access. When you eat carbs, excess glucose is stored as glycogen first (muscles hold ~400g, liver ~100g). Only after glycogen stores are full does excess glucose convert to fat.

Fiber — structurally a carbohydrate, but your enzymes can’t break it down. Instead, your colonic bacteria ferment it. This makes fiber fundamentally different from starch or sugar — it feeds your gut, not your bloodstream. See the fiber section below.

Sugar, glucose, fructose, glycogen — what’s what

These terms get used interchangeably, but they mean different things:

Term	What it is	Where it comes from	Where it goes
Sugar (common use)	Umbrella term — usually means sucrose (table sugar), but also used loosely for any simple carbohydrate	Sugarcane, sugar beet, added to processed foods, naturally in fruit and dairy	Split into glucose + fructose (if sucrose) → each follows its own path
Glucose	A single sugar molecule — the universal fuel	Breakdown of starch and sucrose; also produced by the liver (gluconeogenesis)	Every cell can use it; excess stored as glycogen, then as fat
Fructose	A single sugar molecule — liver-only fuel	Fruit, honey, high-fructose corn syrup, sucrose	Almost entirely processed by the liver; excess → fat (de novo lipogenesis)
Glycogen	A branched chain of glucose molecules — your body’s storage form of carbs	Built from glucose after you eat carbs	Stored in muscles (~400g) and liver (~100g); broken back down to glucose when needed

The practical difference: when someone says “sugar is bad,” they usually mean excess sucrose or high-fructose corn syrup — not the glucose your muscles need after training. Context matters.

Glucose and glycogen — your energy storage system

Your body doesn’t just burn glucose the moment you eat it. It stores large amounts as glycogen for later use — and how full or empty those stores are affects your energy, performance, and whether excess carbs end up as fat.

How glycogen is formed (glycogenesis)

After you eat carbs:

1. Digestion breaks them down to glucose
2. Glucose enters the bloodstream → blood sugar rises → pancreas releases insulin
3. Insulin signals muscle and liver cells to take up glucose (via GLUT4 transporters in muscle, GLUT2 in liver)
4. Inside the cell, glucose is phosphorylated (locked in) and the enzyme glycogen synthase chains glucose units into branched glycogen molecules
5. The process continues until glycogen stores are full

Key point: glycogen storage has a ceiling. Your muscles hold roughly 400g (~1,600 kcal) and your liver holds roughly 100g (~400 kcal). Once full, additional glucose has nowhere to go as glycogen. The body can convert excess glucose to fat through de novo lipogenesis (DNL), but quantitative studies (Hellerstein 1996) show hepatic DNL is actually quite limited on normal mixed diets — typically contributing <5g/day of new fat. The primary mechanism by which excess carbs cause fat gain is suppression of fat oxidation: when glucose is abundant, the body burns glucose preferentially and stores incoming dietary fat instead. DNL becomes quantitatively significant only under chronic massive carbohydrate surplus (>500g/day sustained) or chronic fructose overfeeding.

Muscle glycogen vs liver glycogen

These two pools serve completely different purposes:

	Muscle glycogen	Liver glycogen
Capacity	~400g (~1,600 kcal)	~100g (~400 kcal)
Purpose	Fuels the muscle it’s stored in — local use only	Maintains blood sugar between meals and during sleep
Access	Can only be used by that specific muscle (no export to bloodstream)	Released into the bloodstream as glucose for the whole body
Depletion trigger	Exercise — especially high-intensity	Fasting, overnight sleep, prolonged exercise
Refill time	24–48 hours with adequate carb intake	12–24 hours

Muscle glycogen is trapped — once glucose enters a muscle cell and becomes glycogen, it stays there. Only that muscle can use it. This is why you can deplete your leg glycogen with squats but still have full arm glycogen.

Liver glycogen is the blood sugar buffer. Between meals and overnight, the liver steadily breaks down glycogen (glycogenolysis) to keep blood glucose stable at roughly 70–100 mg/dL. When liver glycogen runs low — after an overnight fast or prolonged exercise — the liver switches to making glucose from amino acids, lactate, and glycerol (gluconeogenesis).

Glycogen and exercise performance

Glycogen is the primary fuel for moderate-to-high intensity exercise. Fat can fuel low-intensity work (walking, easy cycling), but once intensity rises above roughly 60–65% of VO2max, your body relies increasingly on glycogen.

What happens when glycogen runs out:

• In endurance sports, this is called “hitting the wall” or “bonking” — a sudden, dramatic drop in performance when muscle glycogen depletes
• Brain fog, heavy limbs, inability to maintain pace — the body is forcing you to slow down
• The liver tries to compensate by making glucose, but gluconeogenesis is slow — it can’t keep up with high-intensity demand

Glycogen supercompensation (carb-loading):

Depleting glycogen through training and then eating a high-carb diet can temporarily increase muscle glycogen stores by roughly 20–50% above normal levels in trained athletes. This is the basis of carb-loading before endurance events. The protocol doesn’t use extreme carb-loading routinely, but timing carb-heavy meals after training takes advantage of the same principle on a smaller scale — muscle GLUT4 transporters are more active post-exercise, so carbs go preferentially to glycogen rather than fat.

Why this matters for the protocol

The klatiPRO approach to carbs connects directly to glycogen biology:

• 150–300g carbs/day — enough to refill glycogen daily for active adults who train 3–6 days per week
• Front-load carbs to morning and pre/post-workout — fills glycogen when muscles are most receptive (insulin sensitivity is typically higher in the morning, and GLUT4 activity is elevated post-exercise)
• 3–4 hour meal spacing — allows insulin to return to baseline between meals so fat burning can resume once glycogen needs are met
• Keto limits high-intensity performance — with under approximately 50g carbs/day, glycogen stores stay chronically depleted; manageable for steady-state activity but limits explosive and high-intensity output (sprints, heavy lifts, HIIT)

Glycemic index and glycemic load

Glycemic index (GI)

Measures how fast a food raises blood sugar compared to pure glucose (GI = 100). Scale:

GI range	Category	Examples
0–55	Low	Most vegetables, legumes, nuts, berries, whole oats
56–69	Medium	Brown rice, sweet potato, whole wheat bread
70–100	High	White bread, white rice, potatoes, cornflakes, watermelon

Problem with GI alone: it’s measured using approximately 50g of carbs from that food in isolation. Most people don’t eat 50g of carbs from watermelon in one sitting. And nobody eats carbs alone — protein and fat in the same meal change the glucose response.

Glycemic load (GL)

A more useful measure: GL = GI × grams of carbs per serving ÷ 100. It accounts for how much carb you’re actually eating.

GL range	Category
≤10	Low
11–19	Medium
≥20	High

Example: watermelon has a high GI (76) but a low GL (~5 per slice) because a serving contains very little carb. White rice has a high GI (73) AND a high GL (~29 per cup) because you eat a lot of it.

Practical takeaway: GL matters more than GI. And both are modified by what else is in the meal — add fat, protein, or fiber and the glucose response flattens.

Fructose — the liver sugar

Fructose deserves its own section because it follows a unique metabolic path that looks remarkably similar to alcohol metabolism.

How fructose is metabolized

Unlike glucose (which every cell can use), fructose goes almost entirely to the liver. There, the liver converts it through a process that:

1. Bypasses the main rate-limiting step in glucose metabolism (phosphofructokinase)
2. Generates substrates that can be converted to fat (de novo lipogenesis)
3. Produces uric acid as a byproduct

At moderate doses (roughly 15–25g per day from whole fruit), the liver handles fructose without problems in most healthy adults. The fiber, water, and micronutrients in whole fruit slow absorption and limit the dose per sitting.

When fructose becomes a problem

At high doses (consistently above 50g/day from added sugars, juice, or excessive fruit), the liver gets overwhelmed:

• Fatty liver — excess fructose converts to fat that accumulates in the liver (non-alcoholic fatty liver disease — NAFLD). The pathway is nearly identical to how ethanol causes alcoholic fatty liver
• Insulin resistance — liver fat accumulation disrupts insulin signaling
• Uric acid elevation — fructose metabolism produces uric acid, which at high levels contributes to gout and may raise blood pressure
• Triglyceride increase — the liver packages excess fat into VLDL (very-low-density lipoprotein) particles, which is associated with elevated blood triglyceride levels

klatiPRO fructose guidelines

• Up to 20g fructose/day for men, 15g for women (roughly 40g / 30g total sugar) — can go slightly higher if training hard
• Get fructose from whole fruit (fiber slows absorption, vitamins add value)
• Avoid fruit juice (same fructose load, no fiber, absorbed much faster)
• Avoid high-fructose corn syrup and added sugars
• Honey is an exception — in small amounts (~1 tsp/day), raw unprocessed honey contains enzymes, antioxidants, and trace compounds that modulate the fructose impact. Still counts toward your daily limit

Resistant starch — fiber in disguise

Resistant starch (RS) is starch that resists digestion in the small intestine and reaches the colon intact, where bacteria ferment it — just like fiber. The most practical type:

RS3 — retrograded starch

When you cook starch and then cool it for 12–48 hours, the starch molecules rearrange into a structure that digestive enzymes can’t easily break down. This is retrograded starch (RS3).

How to create it:

1. Cook rice, potatoes, oats, or plantains
2. Cool in the refrigerator for 24–48 hours
3. Eat cold or reheat — reheating doesn’t fully reverse the retrograding

What it does:

• Reaches the colon → bacteria ferment it → produces butyrate and other short-chain fatty acids (SCFAs)
• Feeds beneficial bacteria (prebiotic effect)
• Lowers the glycemic response of the meal (lower GL)
• Increases satiety

This is why the klatiPRO protocol specifically recommends cooking starch and then cooling it. Cold potato salad, overnight oats, and cooled basmati rice all contain significantly more resistant starch than their freshly cooked versions.

See gut health: dietary fiber by type for more on resistant starch and other prebiotic fibers.

Fiber types and why they matter

Fiber is technically a carbohydrate, but your body treats it completely differently from starch or sugar. Your digestive enzymes can’t break it down — instead, it passes through to the colon where bacteria ferment it.

Soluble fiber

Dissolves in water to form a gel-like substance. This gel:

• Slows gastric emptying → you feel full longer
• Slows glucose absorption → flattens the blood sugar curve
• Binds bile salts → forces liver to make new bile from cholesterol → associated with lower blood cholesterol levels in studies
• Fermented by bacteria → produces SCFAs

Sources: oats (beta-glucan), legumes, apples (pectin), citrus (pectin), psyllium husk, barley

Insoluble fiber

Doesn’t dissolve in water. Adds bulk to stool and promotes regular bowel movements.

• Speeds transit time through the colon
• Reduces contact time between potential carcinogens and the colon wall
• Less fermentable than soluble fiber

Sources: wheat bran, vegetables (celery, green beans, cauliflower), whole grains, nuts, seeds

Specific fiber types

Fiber type	Found in	Key benefit
Beta-glucan	Oats, barley, mushrooms	Lowers LDL cholesterol; immune modulation
Pectin	Apples, citrus, berries	Binds bile salts; slows glucose absorption
Inulin / FOS	Chicory root, garlic, onion, asparagus, artichoke	Strongly prebiotic; feeds bifidobacteria
Resistant starch	Cooked-then-cooled starch	Butyrate production; glycemic control
Psyllium	Plantago seed husks	Gel-forming; improves both constipation and diarrhea
Lignin	Wheat bran, flaxseed, vegetables	Antioxidant; binds bile acids

How much fiber

Research consistently shows optimal benefits at 25–29g/day. Higher intakes (30–40g+ per day) show continued benefits in studies of generally healthy adults, but with diminishing returns. Most Western diets average only 15g/day.

Important: increase fiber gradually. Jump too fast and you’ll get gas, bloating, and discomfort as your gut bacteria adjust to the increased substrate. Also drink enough water — fiber absorbs water, and insufficient hydration with high fiber intake causes constipation, not relief.

Carb timing

When you eat carbs matters — independent of how much you eat.

Front-load carbs

The klatiPRO protocol puts most carbs earlier in the day (breakfast, lunch, pre-workout). This aligns with your body’s natural insulin sensitivity rhythm:

• Morning: insulin sensitivity is highest — your muscles and liver are most responsive to glucose uptake
• Evening: insulin sensitivity drops — the same carb load produces a higher blood sugar spike and more insulin secretion at dinner than at breakfast
• Post-workout: muscle glycogen is partially depleted — carbs replenish stores efficiently with less likely fat storage

Insulin and meal spacing

Insulin is released every time blood glucose rises. Its job is to shuttle glucose into cells. When insulin is elevated, fat burning is suppressed — your body prioritizes handling the incoming glucose.

The protocol spaces meals 3–4 hours apart so insulin returns to baseline between meals. This creates windows where the body can access stored fat for fuel. Constant snacking (even “healthy” snacks) keeps insulin elevated and locks fat stores.

See fasting and meal timing for the full picture.

Carb sources — what the protocol uses

Recommended sources

Food	Why it works
Potatoes (boiled, then cooled)	High potassium, moderate GI when cooled (RS3), versatile
Basmati rice (rinsed)	Lower arsenic than other rice types when rinsed and cooked with excess water; lower GI than jasmine or short-grain
Oats (steel-cut or rolled)	Beta-glucan (soluble fiber), slow-releasing; overnight oats provide RS3
Sweet potatoes	Lower GI than white potatoes, high beta-carotene
Plantains (ripe or green)	Green plantains = high resistant starch; ripe = more sugar but still good
Fruit	Whole fruit (not juice): fiber slows fructose absorption; berries, citrus, kiwi are best

Arsenic in rice

Rice accumulates inorganic arsenic from soil and water — a legitimate concern, not a myth. Arsenic content varies by origin and type:

Higher arsenic: rice grown in central/southern US (historical cotton fields with arsenic-based pesticides), some Chinese and Indian rice Lower arsenic: basmati from India/Pakistan (paradoxically, despite being Indian, basmati specifically tests lower), jasmine from Thailand, California sushi rice

How to reduce arsenic 40–60%:

1. Rinse rice thoroughly (3–4 washes until water runs clear)
2. Cook in excess water (6:1 water:rice ratio) and drain — like pasta
3. This removes water-soluble arsenic but also some B vitamins and starch

Sources to avoid or limit

• White bread, pastries — high GI, refined flour, rapid glucose spike
• Fruit juice — same fructose as whole fruit but no fiber; absorbed too fast
• Sugary cereals — sugar + refined grains + minimal fiber
• Sugar-sweetened beverages — liquid fructose; the worst possible carb delivery

Sugar alcohols

Sugar alcohols are carb-derived sweeteners that partially resist digestion. The protocol allows a few in small amounts:

Sweetener	GI	Calories/g	Notes
Erythritol	0	0.2	No blood sugar effect; doesn’t reach the colon in most people. ⚠️ High doses (>50g) may cause GI discomfort. ⚠️ Cardiovascular concern: a 2023 Nature Medicine study (Witkowski et al., 3 cohorts, n>4,000) found circulating erythritol associated with 80–121% higher MACE risk; a 2024 interventional follow-up showed 30g erythritol enhanced platelet reactivity in all healthy subjects. Observational + mechanistic — not causal proof, but warrants caution pending further research
Allulose	0	0.2–0.4	Rare sugar; absorbed but not metabolized; some evidence of anti-diabetic effects. Limited availability. No cardiovascular safety concerns reported to date
Xylitol	7	2.4	Dental benefits; fermented by gut bacteria → gas at higher doses. ⚠️ Cardiovascular concern: a 2024 European Heart Journal study (Witkowski et al., n>3,300) found xylitol associated with 57% higher MACE risk and enhanced thrombosis in vivo; 30g consumption enhanced platelet measures in all healthy volunteers. Same caveats as erythritol — observational + mechanistic, not yet causal
Monk fruit	0	0	Extract from luo han guo; 150–300× sweeter than sugar; no GI impact
Stevia	0	0	Plant extract; can have bitter aftertaste; some people metabolize it differently

The protocol position: these are acceptable in small amounts for people who need sweetness. They’re not health foods. Real food is generally better than sweetened alternatives. Updated caution (2024): emerging research from Cleveland Clinic links erythritol and xylitol to enhanced platelet reactivity and higher cardiovascular event risk in observational cohorts. These findings are preliminary (same research group, observational + small interventional arms, cardiac patient populations), but the mechanistic signal is consistent. Until larger independent studies confirm or refute these findings, the protocol recommends limiting erythritol and xylitol intake — allulose, monk fruit, and stevia do not share this signal and remain preferred alternatives.

How much carbohydrate

The protocol targets 150–300g per day for active adults, depending on:

Factor	Lower end (150g)	Higher end (300g+)
Activity	Sedentary / light training	Heavy training / 2×/day
Goal	Fat loss / body recomposition	Performance / muscle gain
Tolerance	Insulin-resistant / metabolic issues	Healthy insulin sensitivity
Diet style	Lower carb approach	Standard balanced

Keto option (under 50g/day): the protocol acknowledges keto as a tool for specific situations in adults — rapid fat loss, metabolic reset, neurological conditions (epilepsy, where it has strong evidence). It’s not the default because sustained very-low-carb limits high-intensity training performance and is harder to maintain long-term for most people. Cycling in and out based on goals is reasonable.

• check klatiCHECK for klati approved sources

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Research