Felicia Newell, RD, MSc
Nutrition Myth Debunked: Avoid Carbs for Fat Loss…and Fat Loss Explained (in a Healthy way)
Updated: Oct 13, 2022
*Trigger warning, discussion of calories and fat loss.
Many people associate carbs with weight gain and believe that the only way to lose weight is by cutting carbs out of their diet. This is a very common misconception in the wellness world.
This is a somewhat half-truth, but for different reasons than expected/promoted. When we consume carbs, we store them as glycogen, and each gram of glycogen is stored with 3-4 grams of water. This means when we restrict carbs, we see an initial loss in water weight, but this is obviously not fat loss. What also tends to happen is because carbs are in so many foods (fruits, veggies, whole grains, dairy, legumes, chips, ice cream, candy, etc.) restricting carbs usually means a severe calorie restriction. A severe calorie restriction (over time) may lead to increased fat loss, but it also can lead to more muscle mass loss, reduced metabolism, impaired hormone function (for some), and more.
Carbohydrates are the macronutrient we require the most. 45-65% of our daily diet should be composed of carbohydrates for our bodies to function optimally, so how does it make sense that if we want to lose weight we must cut these out of our diets?
Carbohydrates are our primary energy source, when we excessively deprive our bodies of this fuel (e.g., less than 5% of our daily calories) our body can enter a state referred to as ketogenesis. You may have heard of the Keto diet before, and this diet derives from the avoidance of carbohydrates. When our bodies run out of the energy provided from carbohydrates we began to use our backup energy source which is our fat storage. This is where the idea comes from that to lose fat we should avoid carbohydrates.
However, when we enter this backup energy source there are side effects that come along with this. It is common for people to experience fatigue, insomnia, brain fog, confusion, and much more. While weight loss is also often a side effect that comes with following this diet this is not because of the avoidance of carbohydrates it is because when we avoid such food group we are often in a caloric deficit whether we know it or not.
Each person is different, so yes, there are some people who feel just fine (for a short period of time) restricting carbs. Also, the placebo effect and the brain are very powerful. For many, expecting to feel better will lead to feeling better. For some others, they are cutting out foods that they may have been eating excessively, such as candy, chips, chocolate, etc., thus causing them to feel better.
Also, there are just as many stories of people who lack success using a keto diet as there are success stories, they just don’t get shared as often. We have worked with many clients who tried Keto or very low carb, and it was not sustainable long-term. Or, they maintained or even gained weight because they ended up eating too many higher calorie keto foods such as bacon, steak, butter, cookies and other treats.
Yes, it is true that foods containing carbohydrates can (key word, can, as there are also many carb containing foods that are low in calories, such as fruits and vegetables) be high calories but this is because they are also packed with energy, nutrients, and minerals are bodies require (e.g., oats, grains, dairy, legumes). Also, many foods that are high in both carbohydrates and calories, also contain fat, such as baked goods.
Carbohydrates, especially less processed, higher fibre carbs, often leave us feeling full for longer and more satisfied and it is possible and encouraged to eat carbs while trying to lose weight. They also contain important prebiotics, which are essential for gut health.
Fat loss explained in (somewhat) simple terms
Please note that fat loss and discussing calories may not be for everyone and that is okay. For many people, fat loss is a goal and they are perfectly fine with talking about calories. For others, after years and years of being in the diet culture cycle, they just need to focus on their relationship with food and focusing on fat loss or calories may be harmful. We are all unique individuals with separate experiences in life. Nutrition advice should be tailored to the person, and the person should have full autonomy with the approach they wish to take to reach their goals.
The simplest way to look at fat loss is to eat less calories than you are expending. Yes, this can be complex as there are multiple factors that can affect the input side of the equation (how much energy we take in), versus the output (how much energy we use/expend) side of the equation. However, we can get a sense of our total daily energy expenditure by using a validated equation such as the ‘Harris Benedict’ (click to calculate your daily needs) equation, which is based on age, gender, weight, height, and activity level.
From there, we want to consume approximately 15-20% deficit of your ‘Total Daily Calorie Needs’, whereas your BMR is the minimal amount you would ever want to eat in a day, and ideally a few hundred calories more than that if you’re active. For example, if your daily calorie needs are 2100, you multiply that by .80 to calculate a 20% deficit, which is approximately 1700 calories daily for fat loss.
This will provide enough fuel to meet basic survival needs plus activities we are doing, but in a slight deficit for fat loss. Again, going to aggressive is not sustainable and can cause the body to slow down metabolism because we’re consistently not getting enough to meet our basic survival needs.
To put this into context, even if someone was lying in a hospital bed all day in a coma, they would still need at least 1400-2000 calories per day or sometimes more (depending on male or female, height, age). So these ‘diets’ that restrict calories so much that you’re not even meeting your basic survival needs, do more harm than good. This is why diet culture is a vicious circle and people have been yo-yo dieting for years.
Yes, of course, we want to ensure that most of the foods we are eating provide nourishment, and help support our goals, but this is going to look different for everyone. For some people, nourishment might look like nourishing their soul with indulgent foods they enjoy after years of restriction, for others, it looks like increasing fruits and veggies because they want to learn to like them better, and increasing fibre for better satiety and digestion. Let's not judge or define what is 'healthy' for everyone.
FYI…the 4 variants of energy expenditure are broken down like this, this is an average;
BMR (basal metabolic rate, aka the calories/energy that is used to perform the billions of chemical reactions needed daily just to keep us alive and our systems functioning) = 70% of TDEE
NEAT (Non-exercise activity thermogenesis, aka the calories burned doing non-exercise activities such as walking, standing versus sitting, fidgeting, etc., which can actually be very helpful for fat loss if you increase this area) = 15% of TDEE
EAT (exercise activity thermogenesis) = 5% of TDEE
TEF (Thermic effect of food, aka calories burned while digesting food) = 10% of TDEE
Our bodies function better when we are consuming carbs and this is because our organs, brain, and entire bodies rely on carbohydrates as our number 1 fueling source. There is no such thing as one type of food being able to make us gain weight or make it impossible to lose weight. The inability to lose weight mainly comes from consuming slightly more calories that what our body naturally needs, over time, and this gets stored as fat for ‘later use’. Which goes back to the hunter-gatherer days when we would have periods of feast or famine. We now have abundant access to highly palatable foods, so it makes sense than many people gain wait over time…and this is okay. Bodies are allowed to change through the seasons of life.
We have to talk about diet culture, because this is where demonizing food groups comes from. The diet industry has grown exponentially in the past decades, and so have toxic wellness influencers, and disordered eating has grown right along with these things.
In order to have a healthy relationship with food, we must move away from demonizing foods and ingredients. Diet culture has a way of using fear mongering to push various agendas, because fear mongering and pushing pain points gets more engagement than the truth – there is no one food that contributes to fat gain like there is no one food/ingredient that promotes fat loss.
More and more wellness influencers are using scary words like ‘toxic’ or ‘harmful’ referring to perfectly healthy foods, because it gets more views and engagement. They don’t use solid data to back their claims, or they cherry pick data done on mice, which is not solid evidence to back up claims. Many are also doctors or claim to be, and have millions of followers (although doctors do not have much nutrition education). If we listened to all the popular wellness influencers out there, we would only have air left to ‘eat’, as there are people making claims against fruits and veggies, meats, gains, oils, legumes, and so much more.
'Let’s normalize critical thinking, and take everything with a grain of salt – if it sounds alarming it is likely untrue. Unfollow elitist creators that demonize foods and use words such as ‘toxic’, as they are the toxic ones themselves and are contributing to diet culture and disordered eating. They also don't take into account the social determinants of health and the many factors that affect food choices (access, health, income, etc.). They promote unnecessary fear and shame when people feel that they cannot meet these unrealistic standards to feed themselves and their families. Follow creators that use solid evidence such as randomized controlled trials and meta-analyses to back their claims.
Some of my fav social media accounts include:
Ig and Tiktok: bdccarpenter, dr_idz, foodsciencebabe, soheefit, fn.health (me! I try anyway)
Tiktok: Dr. Karan Raj, andydoeshealthy, andyfvng, fnhealth (me!)
Increasing fruit and vegetable intake, aiming for 25-40 grams of fibre daily, getting adequate protein, increasing physical activity, aiming for 10,000 steps a day are just a few simple ways that help promote fat loss.
Cutting out certain foods is never the best way to lose weight, more often than not it results in failed weight loss or unmaintainable weight loss, and can even contribute to eating disorders…which no food is more detrimental than disordered eating.
For help with taking control of your health and developing a healthy relationship with food, using a personalized approach, feel free to check out the shop page for booking options, or reach out to firstname.lastname@example.org with any questions (and no pressure to book!).
Part of this article was drafted by Morgan Shears, fourth year student dietitian and Certified Eating Disorder Responder. The article was then reviewed and additional content/concepts added by Felicia Newell, RD.
Felicia Newell is a Registered Dietitian, Nutritionist, Food and Nutrition Expert, Health Coach, and a mom of 4 kids under 12. She is also the owner of Sustain Nutrition/FN Health. Felicia wears many hats, and knows what it is like to try and live healthy in a busy world, where our environments aren't always supportive of making healthy choices. Life is busy, confusing at times, and full of contradictions, especially in the world of health and wellness. Felicia is passionate in helping others fight through the misinformation out there, and to navigate life and health, but most importantly, to enjoy it while doing it. She has over 12 years of education and experience in Nutritional Sciences. Between completing her Bachelor and Masters in Nutritional Sciences, working at a research centre, teaching university courses, years of nutrition counselling helping people crush their goals, and being a busy mom of 4, she has the passion, skills, education, and experience to help you reach your health and wellness in a way that works for YOU.