How to Start Keto: Your Complete Week 1 Guide

Ready to start keto but not sure where to begin? You're in the right place. This guide walks you through everything you need to know for a successful first week, with no confusion and no guesswork.

The short version: To start keto, drop your carbs to 20-30 grams of net carbs per day, eat protein and natural fats until satisfied, and replenish electrolytes (sodium, potassium, and magnesium) from day one. Most people reach ketosis (the fat-burning state where your liver makes ketones for fuel) within 2 to 4 days.¹

I've helped hundreds of people start keto, and the ones who succeed all have one thing in common: they prepared properly before day one. That's what this guide is for. Follow these steps and you'll avoid the most common beginner mistakes that derail people in their first week. New to the basics? Start with our Keto Basics guide and What Is the Keto Diet? before day one.

What You'll Learn in This Guide

• How to prepare your kitchen and mindset before starting
• What foods to eat (and avoid) from day one
• How to set your macros correctly
• The electrolyte protocol that prevents keto flu
• What to expect each day of week one
• A simple 7-day meal plan to follow

Let's get you started.

Before Day 1: Preparation (Do This First)

The work you do before starting keto matters more than most people realize. Spend 1-3 days on this prep work and your first week will be much easier.

Step 1: Clean Out Your Kitchen

If it's in your house, you'll eat it. Remove (or hide) these foods:

Throw out or donate:

• Bread, pasta, rice, cereal, crackers
• Chips, pretzels, popcorn
• Candy, cookies, ice cream
• Sugary drinks, juice, soda
• Potatoes, corn, beans
• Low-fat and "diet" products (often high in sugar)

Keep out of sight:

• Foods for family members who aren't doing keto
• Anything that triggers your cravings

This isn't about deprivation. It's about removing decisions. When you're tired and hungry on day 3, you don't want cookies staring at you from the pantry.

Step 2: Stock Your Kitchen with Keto Staples

Here's your essential first-week shopping list:

Proteins:

• Eggs (2-3 dozen, you'll use these constantly)
• Ground beef
• Chicken thighs or breasts
• Bacon
• Deli meat (check for no added sugar)

Fats:

• Butter (real butter, not margarine)
• Olive oil
• Avocados (3-4)
• Cheese (cheddar, mozzarella, cream cheese)
• Heavy whipping cream

Vegetables:

• Spinach or mixed greens
• Broccoli
• Cauliflower
• Zucchini
• Asparagus

Pantry Items:

• Salt (you'll need more than you think)
• Beef or chicken broth/bouillon
• Almonds or macadamia nuts
• Mustard, mayo, hot sauce (check labels)

For a more complete list, see our Keto Shopping List.

Step 3: Get Your Electrolytes Ready

This is the step most beginners skip, and then they feel terrible by day 3.

When you cut carbs, insulin drops and your kidneys excrete more sodium and water, taking other electrolytes with it. If you don't replace them, you'll often get headaches, fatigue, muscle cramps, and brain fog. This is "keto flu," and it's largely preventable by replenishing fluids and electrolytes.²

What to buy:

Budget option: Table salt + Lite Salt (Morton's or Nu-Salt) + a bottle of magnesium glycinate. Total cost: under $15.

Convenient option: A keto electrolyte mix like LMNT, Keto Vitals, or Dr. Berg's. More expensive but easy.

Step 4: Calculate Your Macros

Before you start, know your targets. Most people reach and stay in ketosis on 20-50g of net carbs per day, and staying at the lower end (20-30g) is the most reliable way to get there in your first week.³ On keto, you're aiming for:

• Carbs: 20-30g net carbs per day (the most reliable level for fast ketosis)
• Protein: 0.7-1.0g per pound of lean body mass⁴
• Fat: Enough to feel satisfied (not a target to hit)

Quick macro calculation:

1. Set carbs at 20-25g (the most reliable level for getting into ketosis)
2. Calculate protein: your goal weight x 0.8 = grams of protein
3. Fill remaining calories with fat

Example for a 160 lb person targeting fat loss:

• Calories: ~1,600-1,800
• Carbs: 20g
• Protein: 100g
• Fat: 120-140g

For detailed calculations and examples, see our Keto Macros Guide.

Step 5: Plan Your First 3 Days of Meals

Don't start without a plan. Know exactly what you'll eat for at least the first three days. Write it down or use the meal plan at the end of this guide.

Simple meals work best for week one. Save the fancy keto recipes for later. Right now you just need to eat low-carb food consistently.

What to Eat on Keto (The Simple Version)

Here's the straightforward breakdown:

Eat Freely

Eat in Moderation

Avoid Completely

For a complete explanation of what counts as net carbs, see Net Carbs Explained.

The Electrolyte Protocol (This Prevents Keto Flu)

Follow this daily protocol starting on day one. Most keto flu symptoms are actually just electrolyte deficiency. Fix this and you'll feel a lot better.

Daily Targets

These are the daily electrolyte ranges commonly recommended for a well-formulated ketogenic diet,⁵ which are higher than standard guidelines because keto increases mineral and water loss:

A quick but important note: if you take blood pressure or heart medication, have kidney disease, or are pregnant, talk to your doctor before adding extra sodium or potassium. Potassium supplements in particular can be unsafe at high doses for some people, so getting most of it from food is the safer route.

Simple Electrolyte Schedule

Morning:

• Add 1/4 tsp salt + 1/4 tsp lite salt to a glass of water
• Drink before or with breakfast

Midday:

• 1 cup bone broth OR another salted water
• Eat avocado or leafy greens with lunch

Evening:

• Take 300-400 mg magnesium glycinate with dinner or before bed
• Salt your dinner generously

Signs you need more electrolytes:

• Headache: usually sodium (drink salted water)
• Muscle cramps: usually magnesium or potassium
• Heart palpitations: usually potassium or magnesium
• Fatigue that won't quit: usually all three

If you feel lousy during week one, try drinking salted water first. Many people feel better within 15-30 minutes.

For more on managing the transition, see our Keto Side Effects Guide.

What to Expect: Day-by-Day Breakdown

Everyone's experience is slightly different, but here's what most people feel during week one:

Days 1-2: The Honeymoon

What happens:

• Your body uses up stored carbs (glycogen)
• You lose water weight, often several pounds, since glycogen holds about 3g of water per gram⁶
• You urinate frequently
• Energy feels normal or even good

What to do:

• Stick to simple meals
• Start your electrolyte protocol immediately
• Track everything you eat (at least for this week)
• Drink plenty of water

Common feelings: Optimistic, maybe a little hungry, possibly a mild headache by evening

Days 3-4: The Dip

What happens:

• Glycogen is depleted, ketone production ramps up
• Your body is between fuel sources
• This is when most people feel worst

What to do:

• Double down on electrolytes: drink salted water 2-3 times
• Don't restrict calories; eat until satisfied
• Skip intense exercise; light walking is fine
• Rest if you need to

Common feelings: Tired, foggy, irritable, headache, possibly nausea

This is temporary. Your body is learning to burn fat. Push through and it gets better.

Days 5-6: The Turn

What happens:

• Ketone production stabilizes
• Your brain starts using ketones for fuel
• Energy begins returning

What to do:

• Continue electrolytes
• Notice how your hunger patterns change (you might not be hungry for breakfast)
• Start adding variety to meals if you want

Common feelings: Energy improving, brain fog lifting, less hungry between meals

Day 7: Momentum

What happens:

• You're likely in ketosis now
• Appetite decreases noticeably
• Mental clarity improves for many people

What to do:

• Celebrate completing week one
• Continue the habits you've built
• Consider testing ketones if you're curious (optional)

Common feelings: More stable energy, reduced cravings, feeling accomplished

Your Week 1 Keto Meal Plan

Here's a simple, no-fuss meal plan to follow. These meals use common ingredients and don't require much cooking skill.

Day 1

Day 2

Day 3

Day 4

Day 5

Day 6

Day 7

Notice: Every day stays well under 20g net carbs. For most people, staying at this level reliably leads to ketosis within a few days (individual carb tolerance varies a bit).

For more meal ideas, check out our Beginner Keto Meal Plan and 7-Day Keto Meal Plan.

Week 1 Tips for Success

Tip 1: Don't Restrict Calories Yet

During week one, focus only on keeping carbs under 20g. Eat enough protein and fat to feel satisfied. Your body is making a major metabolic shift. Don't stress it further by undereating.

Calorie restriction can come later once you're fat-adapted (usually week 3-4).

Tip 2: Salt Everything

Seriously. Salt your eggs, salt your meat, salt your vegetables. When you cut carbs, you need more sodium than you're used to. This single habit prevents most keto flu symptoms.

Tip 3: Keep Meals Simple

Week one isn't the time for complicated keto recipes. Stick to:

• Protein + fat + low-carb vegetable

That's it. Fancy recipes can wait until you have the basics down.

Tip 4: Drink More Water Than You Think

Aim for at least 2-3 liters (64-100 oz) daily. Your body is flushing water as it depletes glycogen. Light yellow urine = good hydration. Dark yellow = drink more.

Tip 5: Don't Weigh Yourself Daily

The scale will fluctuate wildly during week one due to water changes. Weigh once at the start and once at the end of the week. Better yet, wait until week 2 or 3 for a more accurate picture.

Tip 6: Tell Someone What You're Doing

Accountability helps. Tell a friend, family member, or join an online keto community. Having someone to check in with makes you more likely to stick with it.

Tip 7: Be Ready for Cravings

You might intensely crave bread, sugar, or your favorite carb-heavy foods around days 3-4. This is normal. It passes. Have keto-friendly snacks ready: cheese, nuts, hard-boiled eggs, olives.

Don't give in. Each day the cravings get weaker.

Common Week 1 Mistakes (And How to Avoid Them)

Mistake 1: Not Getting Enough Electrolytes

The problem: You feel terrible and assume keto "isn't working" or "isn't for you."

The fix: Follow the electrolyte protocol above. Most people who quit in week one are actually just sodium-deficient.

Mistake 2: Eating Too Little

The problem: You cut carbs AND calories at the same time, leaving you exhausted and starving.

The fix: Eat enough. If you're hungry, eat more protein and fat. Calorie restriction comes later.

Mistake 3: Expecting Instant Results

The problem: You weigh yourself on day 3, don't see a miracle, and get discouraged.

The fix: Give it the full week minimum. Fat adaptation takes time. The first few days are water fluctuation, not fat loss.

Mistake 4: Going Nuts on "Keto Products"

The problem: You buy every keto bar, keto bread, and keto dessert at the store, eat way more carbs than you realize, and never get into ketosis.

The fix: Stick to whole foods for week one. Eggs, meat, vegetables, cheese. Keto products often contain sweeteners that affect some people or have misleading net carb counts.

Mistake 5: Exercising Too Hard

The problem: You try to do your normal workout routine on day 2 and feel like death.

The fix: Light activity only during week one. Walking is great. Save the intense workouts for week 2 or 3 when your energy returns.

Frequently Asked Questions

How do I know if I'm in ketosis?

Common signs include: decreased appetite, increased thirst, fruity or metallic breath, more mental clarity, and more stable energy. For confirmation, you can use urine ketone strips (cheap but less accurate) or a blood ketone meter, which is the most accurate option and reads nutritional ketosis at 0.5 mmol/L or higher.⁷

What if I accidentally eat too many carbs?

Don't panic. It happens. One meal won't ruin everything. Just get back on track with your next meal. If you went significantly over (like eating a whole pizza), you might be out of ketosis for 1-2 days. Resume strict keto and you'll be back.

Can I drink alcohol during week one?

I'd recommend avoiding it. Your liver processes alcohol before fat, so drinking pauses fat burning, and alcohol can worsen keto flu symptoms while your tolerance drops.⁸ If you do drink, stick to spirits (vodka, whiskey, tequila) with zero-carb mixers or dry wine. Skip beer entirely.

I'm not hungry, should I force myself to eat?

No. Reduced appetite is a normal keto benefit. If you're not hungry at breakfast, skip it. Just make sure you're getting enough protein when you do eat (aim for roughly 0.7-1.0g per pound of lean body mass daily).

Is it normal to feel tired and foggy?

During days 2-4, yes. This is the transition period. If it continues past day 5-6, you're likely not getting enough electrolytes. Increase sodium first, then check magnesium and potassium.

How much weight will I lose in week one?

Most people lose about 2-8 lbs in week one, but this is mostly water weight.⁹ When you deplete glycogen, you release the water stored with it (roughly 3g of water per gram of glycogen). True fat loss becomes visible in weeks 2-4.

Do I need to buy a ketone meter?

No, it's optional. If you eat under 20-30g net carbs daily, you'll typically be in ketosis within 2-4 days. A meter provides confirmation but isn't necessary. Urine strips are a cheaper alternative if you want some feedback.

After Week 1: What's Next

Congratulations, you made it through the hardest part. Here's what comes next:

Week 2: Energy stabilizes, cravings diminish significantly, you can start light exercise. Continue electrolytes.

Weeks 3-4: You're becoming fat-adapted. Energy is consistent, appetite is controlled, mental clarity improves. You can start adjusting calories for weight loss if that's your goal.

Month 2+: Keto becomes second nature. You can experiment with recipes, try intermittent fasting if interested, and find your sustainable long-term approach.

Key Takeaways

• Prepare before starting: Clear your kitchen, stock keto foods, get electrolytes ready
• Keep carbs under 20g net for week one to reliably reach ketosis for most people
• Electrolytes are essential: Sodium, potassium, magnesium, start from day one
• Expect days 3-4 to be the hardest: push through and it gets better
• Eat enough protein and fat: Don't restrict calories in week one
• Keep meals simple: Protein + fat + low-carb vegetables
• Give it the full week before judging results

What to Read Next

• What Is the Keto Diet?
• Keto Macros: How to Calculate Fat, Protein, and Carbs
• Keto Side Effects and How to Fix Them
• Beginner Keto Meal Plan
• Keto Shopping List

Sources

• Healthline - The Ketogenic Diet: A Detailed Beginner's Guide to Keto
• Cleveland Clinic - 'Keto Flu': What It Is and How To Manage It
• Diet Doctor - Keto Diet for Beginners
• Harvard T.H. Chan School of Public Health, The Nutrition Source - Diet Review: Ketogenic Diet for Weight Loss
• Virta Health - How much sodium, potassium and magnesium should I have on a ketogenic diet?
• NIH Office of Dietary Supplements - Magnesium Fact Sheet for Health Professionals
• NCBI/PMC - The Potential Health Benefits of the Ketogenic Diet: A Narrative Review