Are Carbs Bad For You?

Low carb diets are often prescribed as the path to weight loss and better health, but is there evidence to support those claims.

If you go searching yourself, you’ll find a lot of confusing and contradictory information out there about whether carbs are good or bad.

Some diets demonize carbs as the root cause of weight gain and obesity, while others argue that carbs are an essential part of a healthy diet.

So what’s the real deal on carbs? Let’s take a balanced look at the facts.

Do Carbs Make Me Gain Weight?

Many people believe that carbs, especially refined carbs like white bread, pasta, and sugar, are fattening and will inevitably lead to weight gain. But the true catalyst for weight gain is consuming more calories than your body burns on a consistent basis – known as a caloric surplus.

To put it simply, too much energy in (food) and not enough energy out (metabolism and activity) leads to weight gain. The laws of physics hold true for human beings.

But let’s explore the different macronutients and see what we can discover.

The Other Macronutients

Carbs contain 4 calories per gram, just like protein. Fat contains 9 calories per gram. So theoretically, you could gain weight eating too many calories from any macronutrient.

In reality, however, it’s easier to overeat calorie-dense foods that are high in fat and refined carbs. Foods like pizza, burgers, fries, cakes, cookies, chips, etc are high in both fat and refined carbs, making them very calorie-dense. Food like those can easily drive caloric intake to a surplus, resulting in the accumulation of body fat.

Eating these foods on a regular basis makes it challenging to maintain a caloric deficit needed for weight loss. But the carbs themselves are not inherently fattening – the total calories matter most.

You could gain weight eating low to no carbohydrate foods. Even on a keto diet that included such foods as bacon and olive oil you can gain weight if you’re in a caloric surplus.

The takeaway here is that the true catalyst for weight gain is a caloric surplus.

Insulin Isn't the Enemy

Some argue that insulin drives fat storage, and eating carbs raises insulin, so carbs make you fat. This is known as the “carbohydrate-insulin model” of obesity.

It’s true that eating carbs triggers an insulin response. Insulin facilitates the storage of energy from food into both muscle and fat cells.

In healthy non-diabetic people, excess calories and nutrients in the bloodstream will eventually get stored as body fat, regardless of whether they come from carbs or fat.

So while insulin plays a role in the process, it does not preferentially drive fat storage from carbs alone.

The Carbohydrate Insulin Model is Wrong.

Decades of research have conclusively shown that the carbohydrate-insulin model for obesity is wrong.

Instead, excess calorie intake drives fat storage and weight gain regardless of nutrients.

This is known as the caloric model of obesity, and it is the accepted explanation among nutrition experts.

So, which Macronutrients Are Most Fattening?

While all excess calories can lead to fat gain, some nutrients are more “adipogenic” meaning they tend to be stored as fat more readily.

It may come as a surprise, but of the three macronutrients, dietary fats tend to be the most adipogenic. Fats require very little conversion to be stored as body fat. Carbs are next – they require some conversion but are still readily stored. Protein is the least adipogenic macronutrient, requiring a lot of conversion.

On average:

Fat > Carbs > Protein in adipogenic potential.

Which is the fancy way of saying that dietary fats become body fat the easiest when in a caloric surplus, with carbs being the second easiest to convert to body fat and protein being the most challenging to convert to body fat.

So if you overeat equal calories of fat or carbs, the fat is marginally, but only marginally, more likely to be stored as body fat.

This doesn’t mean that you should avoid fats or carbohydrates, the difference in tehir potential to be stored as fat is only marginal.

Instead, it’s import to remember that:

Excess calories from any macronutrient will lead to fat gain over time.

Can I Eat Carbs and Lose Weight?

Absolutely! Despite fears about carbs, numerous studies show that you can lose weight effectively on a weight loss diet that includes carbohydrates.

A meta-analysis of 32 controlled trials found that low carb and low fat diets resulted in similar amounts of weight loss over a period of 12 months. Researchers concluded that both low carb and low fat diets work for weight loss as long as they maintain a caloric deficit.

Even for individuals with obesity and type 2 diabetes, weight loss diets higher in carbs (60% of total calories from carbs) have been shown to be effective for losing weight and improving symptoms, as long as total calories are reduced to create a deficit.

The key is that:

Any diet that reduces your overall calorie intake can result in weight loss

regardless of the ratio of carbs, protein, and fat. Weight loss ultimately comes down to calories in versus calories out.

So, yes, you can lose weight eating carbs.

Do I Need to Limit Carbs to Lose Weight?

To recap – no, reducing carbs is not required for weight loss.

You can lose weight on a reduced-calorie diet that includes carbs. The most important factor is creating that caloric deficit through portion control, food choices, and activity levels.

That said, limiting carbs can help certain individuals better manage hunger levels and stick to their calorie goals. Cutting back on carbs eliminates a lot of highly palatable, calorie-dense food options. This can reduce overall calorie intake to promote weight loss.

Some people do really well on a low carb or ketogenic diet approach for weight loss.

But others struggle with cravings, irritability, fatigue and poor workout performance without enough carbs. People have varying degrees of carbohydrate tolerance and metabolism.

The Benefits of Keeping Carbs In Your Diet

Although it may seem counterintuitive to some, including carbs in a fat loss or weight loss diet has its advantages. Carbs provide several important benefits that may help your fat loss diet:

  • Carbs give you energy to fuel tough workouts and build/maintain muscle mass. Limiting carbs can reduce performance.

  • Carbs aid workout recovery. Without enough carbs, muscles recover slower.

  • Carbs help spare muscle loss on a diet. They supply calories so your body doesn’t break down protein from muscles.

  • Carbs promote deep, restful sleep which supports fat loss.

For these reasons, there are advantages to keeping carbs in your diet if possible. You want to preserve workout intensity and avoid muscle breakdown.

Of course calories still matter. You may need to cut some carbs to create a deficit. But try to keep enough in your diet for performance, recovery and muscle retention.

Keeping carbs can fuel your fat loss diet.

Can I Lose Weight On a Low Carb Diet?

While reducing carbs is not required for fat loss, some people may prefer a low carb approach for a variety of reasons.

Lower carb diets have been shown to be effective for weight loss in research studies.

So yes, you can absolutely lose weight by restricting carbohydrates. Here are some of the proposed mechanisms by which low carb diets may have a metabolism advantage for some people:

  • Reduced appetite and hunger. For certain individuals, minimizing carbs leads to lower appetite and better satiety compared to eating the same calories with more carbs. This spontaneous reduction in calories can lead to weight loss over time.

  • Lower insulin levels. Carbs trigger insulin release, while protein and fat have minimal effects on insulin. Some theorize that chronically lower insulin levels may favor fat loss. However, the energy balance (calories in vs out) still dictates weight changes.

  • Increased ketosis. When carbs are very low, the body relies more on fat breakdown for fuel. This increase in fat burning may help accelerate weight loss. However, studies show this metabolic advantage may be transient.

  • Improved body composition. Some research finds that low carb dieters lose more fat mass relative to lean mass versus low fat dieters when protein intake is matched. This results in a better body composition.

So in summary, yes – restricting carbs often leads to weight loss. A low carb diet can be a viable and effective approach for many people to consider. But it’s still not mandatory for fat loss.

The key is finding the carb intake you prefer that optimizes fat loss while supporting your lifestyle and nutrition preferences. Being consistent with any approach that maintains a calorie deficit will move the needle on your weight over time.

Making the Call: Is Low Carb or Low Fat Better For You?

Research shows that both carb-restricted diets and fat-restricted diets can be effective for weight loss and fat loss over time, as long as they maintain an overall calorie deficit.

But which one should you choose? Here are some factors to consider:

  • Current eating habits – Pick the approach that will require the fewest drastic changes to your current diet and lifestyle. Small sustainable changes in eating patterns are best for long term success.

  • Food preferences – Do you enjoy fatty cuts of meat, butter, oils and full-fat dairy? Or do you prefer carbs like breads, rice, potatoes and sweets? Reduce the foods you’ll miss the least.

  • Meal planning and cooking – If you rely on quick and convenient carb-based foods daily, a low fat diet may be easier to stick to. If you love to cook using fats for flavor, lower carb may fit better.

  • Energy needs – Low carb diets may negatively impact intense training if you’re an athlete or bodybuilder. The optimal carb intake varies based on activity levels.

  • Metabolic effects – Monitor hunger cues, energy levels, mood and cravings and see if you respond better to a lower carb or lower fat approach. Our bodies respond differently.

  • Health conditions – Get guidance from your doctor if you have diabetes, heart disease, thyroid disease or other medical considerations.

The best diet for you is the one you can follow consistently while meeting your nutritional needs.

Try out both approaches and see which feels more realistic and sustainable or hire a qualified coach to help you navigate approaches and create strategies that fit into your unique circumstances, goals, and preferences. Behavior Science-Powered 360 Wellness Certified Coaches can help you

And remember, fat loss will follow if you maintain a calorie deficit – regardless of your carb or fat ratio.

Best Practices for Fat Loss

Here are some best practices regarding carbs for a fat loss diet:

Establish a Caloric Deficit:

If you feel better and find adherence easier on a lower fat diet, then cut back on added fats/oils, fatty meats, whole milk dairy, bacon, butter, gravy, salad dressing, etc. This can often create a solid calorie deficit for many without a massive disruption to your lifestyle.

If you feel better and find adherence easier on a lower carb diet, limit sugar, sugary drinks, excessive alcohol, sweets, and desserts. These provide almost zero nutritional value.

Understand the Hazard of high Carb/Fat Combos:

Foods like pizza and fries pack a massive caloric load and are easily overconsumed, pushing you into a caloric surplus which leads to weight gain. You don’t necessarily need to eliminate these foods, but you do need to move your behaviors toward the healthier end of the spectrum. For example, some people may be able to reduce their weekly pizza indulgences from 4 times per week to two times per week and see progress on their weight loss journey.


Pay attention to overall daily calorie and macronutrient balance rather than a single meal. Be consistent over days and weeks.


Try an approach and see if it is the optimal diet for your body and preferences.

Get a Guide

Fitness professionals certified in 360 Wellness Coaching can guide you to a plan that matches your goals, personality, environment, and preference so you don’t have to rely on discipline and will power to adhere to a plan.

You’ll find the strategies they create for you to be easier and more enjoyable than any previous weight loss attempt.

The Bottom Line:

Carbs do not uniquely cause fat gain.

You can absolutely lose fat while eating a fair amount of quality carbohydrates.

Focus on creating a calorie deficit and being consistent over time. Finding the specific carb level that works for you and supports your lifestyle is the key.