Is it “better” to eat low carb high fat for weight loss?
When I say the term “better,” like I did in the title, let me clarify that every person is a unique individual with unique biological factors, goals, and preferences. So, there is not one diet that is considered the better one for all people, but we’re going for what works for most people, generally speaking.
I tricked you just a bit with the title because there is technically no best diet for fat loss since what works for one person may not work for another. If a certain way of eating works for you and it’s sustainable over time, then I’m all for it!
The question should not be “what is the best diet?” It should be “what works for my body and my goals and what is sustainable for me?”
However, I know that there is a pervasive idea or thought process embedded in our culture that carbs are bad and the best way to lose fat is by cutting carbs out of your diet.
It frustrates the heck out of me that there are so many women who are literally scared to even think about eating carbs, much less consume them. And if you’ve listened to me on the podcast or ready my blog posts, you know where I stand on this issue. I believe balance is needed in your diet so you’re getting the energy you need and the micronutrients you need (vitamins and minerals from different sources).
There are so many misconceptions about carbs that are just not founded in facts. And it’s okay that you may not know the truth because this isn’t your job… you’re not a researcher, you’re not a nutrition coach, or a health expert. It’s my job to uncover the truth and bring it to you without bias and without preconceived notions. I do my scholarly research, I study textbooks about nutrition, and I do my best to make it applicable to real life.
So, we’re going to do a little digging today into the research and I’m going to present you with the results of the studies and break it down for you. I’m NOT telling you how to eat or what to eat. I’m simply giving you the facts that I’ve learned in my research and through my nutrition certification so you can make educated decisions for your eating habits and lifestyle.
So, let’s first discuss the claims of the paleo and ketogenic eating styles:
Advocates of the paleo diet claim that our ancestors mainly lived on diets that were high in fat and protein and that starches were not a part of their daily consumption. However, there is evidence based on the historical data collected by researchers showing that the diet of those who lived over 50,000 years ago was in fact relatively high in carbs with varying levels of fat, depending on the type of meat that was eaten. Our ancestor’s diet typically consisted of approx. 35% of energy from fats, 35% from carbs, and 30% from proteins.
Now, as I’m giving percentages, just understand that we’re talking a percentage of total daily caloric intake. So, for instance, if you’re eating 2,000 calories a day with 35% of your calories coming from carbs, you’d be eating about 700 calories worth of carbs.
In 2018, a 5-year study was done on the Tsimane population in South America. This tribe eats about 14% protein, 14% fat, and as much as 72% of carbs. So, they live off a very carb-rich diet with just a few staple foods like rice and plantain… 2/3 of their diet actually. So, you’d think they’d be low in micronutrients, vitamins, and minerals, right? However, they are reported to not have as many vitamin and mineral deficiencies as other populations, including the U.S.
People of this tribe showed high absorption levels of potassium, magnesium, and selenium which helps to enhance cardiovascular health. They have the lowest reported levels of chronic disease of any population. So, researchers suggest that it is not the quantity of carbohydrates that are a key factor, but the quality of the carbs.
They’re not eating Doritos and ice cream. They’re eating whole foods that are nutrient dense and they’re an overall healthier population because of that.
Now, for my keto enthusiasts, or those thinking about going keto… the claim here is that in response to the reduced availability of glucose and lower insulin values, the body should enter a state of increased fat burning, leading to ketosis.
The goal here is to stay under 50g of carbohydrates per day as the body turns fat and protein into glucose through something known as gluconeogenesis, which is just the production of glucose from a non-carbohydrate source.
To clarify, our body prefers to use glucose for energy and it’s the main source of fuel for our brain, so it is 100% necessary for our bodies to function. Our first source of glucose is from carbs. If we’re not eating enough carbs our body can turn fat and protein into glucose (gluconeogenesis). However, the body does prefer carbs as its source of glucose. Now when the production of glucose by gluconeogenesis is too low to cover the body’s energy need, ketone bodies will be produced as an alternative.
In this state of ketosis, insulin levels in the blood will be low which reduces the stimulus for fat and glucose storage.
If you don’t know, insulin is a hormone that is responsible for the allocation of excess energy… so it can tell your body what to do with the calories that you’re consuming, either being stored as fat or to be used for energy. Insulin also helps our cells convert glucose into energy to be used.
So, in a nutshell, ketones are like a back up emergency generator for when there’s a power outage or a lack of energy in our case. The consensus made by keto advocates is that by reducing or eliminating carbs, the body adapts by using fat for fuel which is, in a sense, true… but not the entire picture.
One meta-analysis of 32 controlled feeding studies found that both energy expenditure (how many calories are burned) and fat loss were greater with low fat diets (not low carb diets), suggesting that the process of ketones and using fat for fuel is not as simple as we’re led to believe and there are likely a lot more factors at play.
Also, while low carb-high fat diets have shown to assist with weight loss, improve insulin sensitivity, and stabilize blood glucose levels, these changes are not just consistent with low carb diets. This suggests that the primary reason for all these positive health effects (enhanced insulin sensitivity and regulated blood glucose) is more likely due to the result of weight loss and not necessarily the result of a reduction of carbs.
Low carb high fat diets do lead to a reduction in appetite, which in turn, helps people to lose weight and then the health results follow.
So yes, keto diets work… but they work just as well as a balanced macronutrient diet. I’ve said it in many posts prior and I’ll say it again, calories are king when it comes to weight loss. It’s the total amount of energy you are consuming versus what your macronutrient split is.
Here’s another study done in 2015:
Dr. Kevin Hall of the National Institute of Diabetes and Digestive and Kidney Diseases did a study of 10 men and 9 women with obesity, with a body mass index of 36. This was a strictly controlled experiment where participants stayed in the clinical research unit for two weeks the first visit and two weeks on another visit. Their diets were controlled and monitored by staff during their visit. On the first visit and first week, participants were given a balanced diet of 50% carbs, 35% fat, and 15% protein at about 2700 calories a day. On the second week of their first stay, they were given 30% fewer calories with the decrease in calories coming from carb cutting. For the next visit, the calorie cut came solely from fat calories.
Researchers found that when participants ate the low carb meal plan, they lowered production of insulin, increased fat burning, and lost about 53grams of body fat per day.
On the low fat diet, there were no changes in their insulin hormone. However, they lost about 89grams of body fat- 68% more than when they cut carbs out.
The takeaway from this scientist is that when comparing reduced fat versus reduced carb diets, the low carb diet was more efficient at lowering insulin and increasing fat burning which did result in body fat loss. However, participants lost more body fat during the restricted fat diet. So ultimately, when it comes to actual body fat loss, it was more efficient to cut calories via fat versus the carbs.
And another one:
This study in 2014 included participants who were overweight/obese, had diabetes, glucose intolerance or insulin resistance, cardiovascular concerns, or risk factors such as hypertension. Treatment diets were low carb weight loss diet plans in two forms: low carb and high fat/protein (unrestricted) OR low carb, recommended fat, and high protein (no restriction on protein). The last controlled diet was balanced macros with similar amounts of calorie intake just with a more balanced macro split. (45-65% carbs, 10-35% fat, and 20-35% protein)
Researchers completed 19 randomized controlled trials (scientific experiment or intervention that aims to reduce any bias during testing) with 3,209 participants.
In the trials with participants without type 2 diabetes, after 3-6 months, the average weight loss in the low carb group ranged from 5.8lbs-22.5lbs., and in the balanced diet group it was 5.8lbs to 20.7lbs. In the 1-2 year follow up, average weight loss for 6.4lbs – 27lbs for the low carb group and 7.7lbs-24lbs with the balanced diet group. So, there was no significant difference in weight loss between the two either in the short term or long term follow up.
For those with diabetes, weight loss after 3- 6 months for the low carb group ranged from 6.2lbs-12.1lbs and for the balanced diet participants the range was 6.8lbs-12lbs. Again, no significant difference.
The key to both groups weight loss successes was the calorie deficit. When it comes to fat loss, total energy intake trumps a certain macronutrient split!
And in looking at other important factors, there was no significant difference in lowered blood pressure or cholesterol levels between the groups.
Resource: Naude, C. E., Schoonees, A., Senekal, M., Young, T., & Garner, P. (2014). Low Carbohydrate versus Isoenergetic Balanced Diets for Reducing Weight and Cardiovascular Risk: A systematic review and meta-analysis. Doi:10.1371/journal.pone.0100652rg
In this short study of 8 weeks in 2017, the treatment concluded that with a steady energy intake during a calorie cut of − 500 kcal/day, a Low Carb High Fat diet is similar to a low-fat high-carbohydrate diet. In this study weight loss was significant in both groups and both groups showed insulin sensitivity improvements. Researchers conclude that Low carb high fat health effects are primarily related to weight loss and the corresponding changes to overall body fat loss and metabolic changes.
Two other reviews concluded that the short-term effects of Low Carb High Fat diets are positive on weight loss and blood glucose management, but also that the long-term effects have not been studied. Researchers say that the observed effects of improved health markers seem to primarily relate to weight loss.
A Downside to Low Carb High Fat Diets:
Researchers believe that a low carb diet, due to low levels of fiber, may lead to negative effects on bowel movements and the production of short-chain fatty acids, which could lead to bowel disease. After a systematic review and meta-analysis Naude et al. concluded that there is probably little or no difference in weight loss and changes in cardiovascular risk factors up to 2 years of follow-up.
Another researcher (Dyson) concluded that low-carb diets for people with type-2 diabetes could in the short-term lead to an improvement in regulation of blood glucose, weight loss, and reduction of cardiovascular risk factors, but that this appeared no longer to be the case in the longer term. Overall, Low Carb High Fat diets did not seem to show any superiority compared to diets with a higher carbohydrate intake. So, he concludes that low-carbohydrate diets are safe in the short term and are effective, but that there are no statistical differences compared with diets containing a higher carbohydrate content. For this reason, Dyson suggests that a Low Carb High Fat diet should not be recommended as the standard treatment of people with type-2 diabetes.
Other researchers agree as they assessed the effects of low carbohydrate diets on probability of mortality, through a meta-analysis. Through analyzing 17 studies of 272,216 people, of which (5.9%) were reported dead, results showed that the risk of mortality with use of of Low Carb High Fat diets was significantly higher.
Because of this, researchers believe that a Low Carb High Fat diet should only be given to people suffering from pre-diabetes or type-2 diabetes, for weight loss and hyperglycemia risk factors. They recommend that the diet only be followed under strict medical and nutritional supervision.
Lastly, researchers found that high fat feeding, which induces low intakes of fermentable dietary fibers, may lead to disruptions in the intestinal microbiota which are linked to an increase in intestinal permeability resulting in inflammation triggers and metabolic disorders.Doi:10.1371/journal.pone.0100652
Resource: Brouns, F. (2018). Overweight and diabetes prevention: is a low carbohydrate-high fat diet recommendable? European Journal of Nutrition 57(4), 1301-1312. Doi:10.1007/s00394-018-1936-y
1. Calories trump macronutrient split when it comes to fat loss. In turn, positive health changes and favorable metabolic shifts occur due to the overall fat loss.
2. While low carb diets are successful interventions for weight loss and health improvement, the studies prove that they are similar to the results of a balanced eating plan. Also, there are not enough studies on the long-term effects of high fat diets to determine if this is a sustainable way of eating.
3. Insulin is not the cause of obesity. Insulin simply instructs your body what to do with excess energy that you consume. Overeating in general is the cause of weight gain. So, while some studies show that low carb does reduce insulin production more effectively (and some studies show similar results of insulin sensitivity with both diets), it does not mean that it’s necessary or indicative of greater fat loss.
4. Some studies show that participants lost more body fat with a higher carb diet versus low carb.
Now again, none of this says that low carb diets don’t work for weight loss. In fact, studies prove that it is an effective method, at least for the short term. Again, complex carbs are the body’s preferred source of glucose (energy) to fuel your muscles, tissues, organs, and the brain. If you can eat carbs, they’re a great healthy source of fuel for you.
Now if your doctor puts you on a low-carb diet for specific health concerns, please follow their medical advice. I’m not a doctor!
But for the rest of us, carbs are a great source for key micronutrients our bodies thrive on. So, my advice is to incorporate nutrient-dense complex carbs into your diet. If you are trying to lose weight, set your maintenance calories yourself or use a coach… like me. If you are going on your own, no problem! Go to google and type in TDEE calculator. Enter the information in the boxes and it will calculate your maintenance calories for you. This calculator is not 100% accurate, but it’s a starting point!
There is a section in the report for “cutting” calories. Use the recommended amount given to you for cutting calories and then set your macronutrient goals.
Set your protein: .8-1.2 grams per pound of body weight
Set your fat: .25-.4g per pound
Now let your carbs take up the rest of the calories you have left over.
If you need help with this, feel free to DM me on Instagram @Bridges2Barbells or use the chat option on my website!
If this information was helpful to you and cleared up some fears/anxieties, I’d love to hear about it! Leave a comment on this post below or head over to my podcast @ Bridges2Barbells Radio (wherever you listen to podcasts) and leave a review for me!
Thank you guys for taking the time to educate yourself on nutrition. I’m so proud of you!
Until next time….
Bye for now!