Why am I gaining weight on low carb diet?

Gaining weight on a low carb diet can be frustrating, but there are several potential reasons why this may happen. In the opening paragraphs, we’ll cover some quick answers to common questions about low carb weight gain.

Quick Answers:

Are you really in ketosis on your low carb diet? Being out of ketosis due to too many carbs or calories can lead to weight gain. Try testing ketones and reducing carbs.

Are you eating too many calories overall? It’s easy to overdo healthy fats and proteins on low carb. Track your calories to be sure you’re not overeating.

Are you intolerant to common low carb foods? Dairy, nuts, and artificial sweeteners cause problems for some people and promote weight gain.

Have you hit a plateau? Stalls and fluctuations are normal. Be patient, double check your tracking, and make small adjustments.

Are you under high stress? Cortisol from high stress can cause fluid retention and blood sugar dysregulation, leading to gains.

Do you have a medical condition? Get lab work done to check for thyroid, hormone, or metabolic issues that may be hindering weight loss.

What causes weight gain on a low carb diet?

There are a few possible reasons why you may hit a weight loss plateau or start gaining weight on a reduced carb diet:

Consuming too many calories

At the end of the day, weight management comes down to calories in versus calories out. If you are consuming more calories than you are burning, you will gain weight. Some common reasons for unexpected calorie surpluses on low carb diets include:

  • Overdoing high fat foods like oils, butter, nuts, seeds, cheese, and fatty cuts of meat
  • Snacking frequently on low carb treats and desserts
  • Drinking a lot of calories from smoothies, nut milks, coffee drinks, diet soda, and alcohol
  • Not tracking your intake accurately
  • Estimating portion sizes instead of weighing food
  • Underestimating calories from cooking oils, dressings, and sauces

To troubleshoot, carefully track your calorie intake for a week while weighing and measuring food. Compare this to your estimated energy needs for weight loss. You may be consuming more calories than realized.

Eating too many carbs

It’s easy to underestimate your carbohydrate intake, especially from vegetables, fruits, nuts, dairy, and artificial sweeteners. Too many carbs can prevent ketosis or knock you out of fat burning mode. Track your total net carbs from all food sources when hitting a plateau. You may find you need to reduce overall carbs to get back into ketosis.

Insulin resistance

A low carb diet can help reverse insulin resistance that makes weight loss difficult. However, some people may struggle with stubborn insulin resistance even when restricting carbs and need to take additional steps. Working with your doctor to test your fasting insulin and A1C can help identify if insulin issues are hindering your efforts.

Sensitivity or intolerance to common low carb foods

Some people do not tolerate certain foods common on low carb and keto diets well. Issues like lactose intolerance, whey or nut allergies, soy intolerance, and reactions to sugar alcohols or artificial sweeteners can all cause inflammation, digestive issues, and weight gain. Try an elimination diet removing suspected foods for 30 days to see if it makes a difference.

Medical conditions

In some cases, an underlying medical condition may be impacting your ability to lose weight. Hormone imbalances like low thyroid, high cortisol, or insulin resistance can make weight loss difficult. Conditions like polycystic ovarian syndrome (PCOS) and Cushing’s disease also commonly hinder weight loss. Getting the right lab tests and working with your doctor can help diagnose any issues.

Too few calories

While less common, some people actually under eat when starting a low carb diet, which can stall your metabolism. Severely restricting calories leads to adaptive thermogenesis, where your body conserves energy by lowering resting metabolic rate. Ensure you are eating at least 1,200 calories per day minimum unless supervised by a doctor.

Water retention

Finally, a scale stall doesn’t always mean you are not losing fat. Fluctuations in water retention can hide weight loss. Eating higher carb or higher sodium meals, menstrual cycles, constipation, exercise, and warm weather can all cause temporary water retention. Use other progress markers like measurements or how your clothes fit to track changes.

How to break through a weight loss plateau on low carb

Sticks and stalls are frustrating but common when losing weight. Here are some tips to overcome plateaus on low carb diets:

  • Track calories accurately for 1-2 weeks and reduce if needed
  • Lower net carbs by 5-10 grams to get into deeper ketosis
  • Cut out artificial sweeteners, dairy, nuts, and alcohol temporarily
  • Check for medical issues with your doctor
  • Drink more water and watch sodium intake
  • Increase activity and add strength training
  • Try intermittent fasting
  • Take a diet break then resume
  • Be patient! Stalls usually last 1-2 weeks

Don’t make too many changes at once. Pick one or two tweaks, give your body time to adapt, and monitor results. Most importantly, stick with it! Consistency is key for breaking through plateaus.

Foods to avoid for low carb weight loss

While individual tolerances vary, here are some common foods to moderate or avoid if struggling to lose weight on low carb:


All grains are high carb and can inhibit ketosis. Avoid bread, pasta, rice, oats, corn, quinoa, crackers, muffins, cereal, etc. Even whole grains are high glycemic.

Starchy vegetables

Higher carb veggies like potatoes, sweet potatoes, peas, parsnips, beans, etc. can add up quickly and should be limited.

Sugar and sweets

Avoid sugary foods like candy, soda, cake, cookies, ice cream, and chocolate. Read labels, as sugar is added to many processed foods.


Fruit is high in sugar, so limit higher glycemic fruits like bananas, grapes, mangos, cherries. Stick to small portions of berries.


All forms of alcohol contain carbs and calories and should be minimized. Dry wines and spirits contain the least carbs.

Artificial sweeteners

Some people react poorly to artificial sweeteners and sugar alcohols. Try eliminating them if stalling.

Nuts and nut butters

Nuts are high in calories and easy to overeat. Measure portions and avoid snacking from the bag.


Dairy like milk, yogurt, and soft cheese is high carb for some. Try reducing or sticking to hard cheeses and high fat dairy.

Processed low carb foods

Many replacement foods like bars and baked goods stall weight loss. Focus on whole foods instead.

Vegetable oils

Vegetable, soybean and canola oils are highly refined and contribute excess omega-6 fats. Opt for olive, avocado or coconut oil.

Tips for successful long term low carb weight loss

Here are some tips for achieving and maintaining weight loss on a low carb diet:

  • Set realistic goals – 1-2 pounds per week is a healthy rate of loss
  • Calculate your macros and track diligently, at least at first
  • Weigh and measure food for accuracy
  • Plan meals and snacks to ensure calorie deficit
  • Include protein, healthy fats and low carb veggies at each meal
  • Stay well hydrated with non-caloric fluids
  • Get plenty of sleep and manage stress levels
  • Stay active with both cardio and strength training
  • Add intermittent fasting if you hit a plateau
  • Allow yourself occasional treats in moderation
  • Seek support and stay motivated!

Reaching your goals takes consistency and patience. Stick with it by making changes you can sustain long term. With the right plan tailored to your needs, low carb diets can give lasting weight loss success.

Frequently asked questions

Why do I lose weight then plateau on keto?

Plateaus are common due to initial rapid water weight loss then a slower fat burning rate. Reduce calories slightly, lower carbs, or try fasting to break the plateau.

Can you gain weight in ketosis?

You can gain weight in ketosis if consuming excess calories. Track intake closely and beware of high fat foods to avoid overeating.

Do calories matter on low carb?

Yes, calories still determine weight loss on low carb. Eat at a modest calorie deficit for steady loss without starvation.

Can dairy stall weight loss on keto?

Dairy may cause inflammation, insulin response, and slow weight loss for some. Try eliminating dairy for 30 days.

Is keto safe long term?

Yes, research shows low carb and ketogenic diets are safe long term for most people. Focus on whole, nutrient-dense foods for sustained health.

The bottom line

Gaining weight while restricting carbs is a common frustration but can be remedied. Track your calories, macros, and net carbs closely. Weigh food and track intake rather than guessing. Control calories from added fats like oils, cheese, and nuts. Consider eliminating common food intolerances like dairy and artificial sweeteners. See your doctor to check for underlying issues. Lastly, be patient and consistent! Fine tuning your diet and sticking with it will help you smash through plateaus.

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