I can hear the pushback from the low-carb devotees already. Before you throw a low-carb cookbook at me, hear me out.
I have written about the value of low-carb diets for years.
A low-carb diet has been the starting point for almost every nutrition plan I have created. Though low-carb is effective for a lot of people, it doesn’t work for everyone. And for some, it works for a while, and then…doesn't.
If you read those last couple sentences and thought, “That’s me!” then this article is for you. It’s also for those who believe a low-carb diet is the end-all, be-all diet for everyone.
Finally, I hope it’s useful for those who offer nutrition coaching, and scratch their heads, wondering why their clients aren’t getting the expected results.
Before delving into why low-carb doesn’t work for some people, I want to highlight what I know and believe about low-carb. I still believe it’s valuable, and a great starting point for most people.
Here’s what I know about low-carb diets
- Low-carb diets minimize elevations in blood sugar and insulin, and improve insulin sensitivity [i],[ii]
- Low-carb diets raise HDL (good) cholesterol and lower triglycerides [iii]
- Low-carb diets have been shown to decrease systemic inflammation [iv]
- Low-carb diets are automatically lower-sugar diets, which is good for everyone
- Low-carb diets decrease belly fat and intramuscular fat (at least in the short-term) [v]
- Low-carb diets have not been shown to negatively impact kidney function [vi]
- Very low-carb diets, or ketogenic diets, are beneficial in those with cardiovascular disease, obesity, metabolic syndrome, type 2 diabetes, and epilepsy, and may be beneficial in those with acne, cancer, polycystic ovary syndrome (PCOS), neurological disease, Alzheimer’s disease, Parkinson’s disease, and brain trauma [vii],[viii]
Here’s what I believe about low-carb diets
- Low-carb diets are not necessary for everyone long-term
- Low-carb diets may be detrimental for high-intensity exercise or athletic performance
- Low-carb diets may contribute to adrenal, thyroid, and gut dysfunction in certain individuals
- Long-term success rates with low-carb diets are not any better than low-calorie or low-fat diets, mainly because people don’t adhere to them
- Many people who are hell-bent on following a low-carb diet do so, even though they do not achieve the health and fitness outcomes they hope for
This is the point I hope to get across with this article:
Even though low-carb diets produce significant effects in many who are overweight, or have a disease, they may not be the optimal diet for everyone.
And with that, I’d like to share with you…
Why You’re Not Losing Weight on a Low-Carb Diet
1. Your low-carb diet is a fat “free-for-all”
As of January 26, 2017, a search on Amazon for “low-carb cookbooks” turns up 6,754 results. That’s a lot of low-carb food porn.
Even on Healthy Living How To, we have a ton of delicious low-carb, dairy-free, gluten-free recipes. However, Vanessa and I eat the Double Mocha Cake, or the Chocolate Covered Bacon, only on special occasions. Even the Meatzza Pizza is a “once-in-a-while” meal.
Most of the time, our low-carb meals consist of meat and veggies, or some eggs with salsa and a low-carb tortilla. They taste good, but certainly not “gourmet.”
We don’t pour extra oil or melted butter on top of our foods, or slather them in cheese or hollandaise sauce, just because it’s “low-carb.”
While you can eat a lot of food on a low-carb diet and experience weight loss, it doesn’t mean you can feast on all the fat you want.
Many people don’t have an appetite on-off switch, even on a low-carb diet. As a result, they consume a ton of extra fat and (yes, I’m saying it) calories. All that extra fat isn’t going to simply pass through you, and you won’t burn it, so it’s going to go somewhere.
Rather than thinking every meal can be gourmet, like many cookbooks suggest, just keep it simple for most of your meals, and save the cookbook recipes for special occasions.
Low-carb eating supports weight loss, but low-carb binging does not.
If you’re lean and healthy, keep dunking your bacon in the leftover bacon grease, and drinking a cup of heavy cream with a shot of espresso. If it isn’t working, though, perhaps your body can’t handle all that extra fat.
2. You are not as low-carb as you think
Whenever I talk to someone about their diet and their weight management goals, I ask two questions:
- How’s your diet?
- What did you eat yesterday?
When I ask the first question, I almost always get the response, “My diet is great. It’s pretty low in carbs.”
Nine times out of ten, they respond to the second question with, “Well…yesterday wasn’t a typical day…” To which I reply, “Okay, what did you eat the day before?” They usually respond, “Hmm…that wasn’t a typical day either.”
When our older son, Jacob, was young, if we asked him a question like, “Do you brush your teeth every day?” he’d respond, “Mostly sometimes.”
An effective low-carb diet isn’t a “Mostly Sometimes Low-Carb Diet.”
In addition, a lot of foods are low in carbs for a single serving. But, you might not be eating a single serving.
A handful of nuts is more than an ounce. You might pour yourself a generous glass of wine. A bar of 80% dark chocolate usually has two to two and a half servings. And the snacks in the office kitchen add up when you stop by a couple times per day.
The worst part is the combination of too many carbs plus all the added fat. It not only keeps you from losing weight but it will also mess up your lipid profile.
An effective low-carb diet is a daily discipline. Once you achieve your goal weight, you might be able to play around with your carbohydrate intake, but not before.
3. Your low-carb diet and high-intensity exercise are not compatible
Crossfit, Alpha, P90X, and other high-intensity training programs require glucose, or glycogen.
In my opinion, combining a high-intensity training program, with a very low-carb diet, leads to chronically elevated cortisol levels. You feel depleted, and over time, your exercise performance will drop while your scale weight will not.
Even for a well-trained athlete, who can handle high-intensity training, a low-carb diet increases cortisol and suppresses testosterone production. For someone who is not adapted to this kind of training, the metabolic effects could be even worse.[ix]
If you don’t manage your cortisol levels, you’ll have a hard time losing weight. You also risk problems with your thyroid function and immune system.
A low-carb diet is effective with low-intensity, aerobic, or endurance exercise. You could even use more of a bodybuilding-type of strength training program, with heavy weights and plenty of rest between sets. But if you want to take part in Boot Camp, it’s best to include some extra carbs to support your training. Or, change your training to complement your low-carb diet.
4. Your low-carb diet is messing up your thyroid
Huh? Isn’t a low-carb diet good for your metabolism?
In some ways, yes. I mentioned many of the benefits at the beginning of this article.
However, long-term, low-carb diets may negatively affect thyroid function.
In the past, I was so focused on the blood sugar, insulin, triglyceride, heart health, and fat-loss benefits of low-carb diets, I dismissed their potential impact on thyroid function.
Low-carb diets have been shown to lower triiodothyronine (T3), your main thyroid hormone. Although thyroxine (T4) levels do go up, T3 is a far more potent thyroid hormone.[x] Since thyroid is the main regulator of your metabolic rate, and also impacts your ability to produce energy and exercise performance, a drop in thyroid function isn’t what you want.
Thyroid also helps maintain normal cholesterol levels. If your thyroid function starts to decline, you might experience a rise in cholesterol.
What should you do?
If your low-carb diet is working for you, keep doing it. If you’ve been telling yourself you’re following a low-carb diet, but you’re not actually sticking with it, then stick with it. And if you're truly following a low-carb diet and it isn’t working, try something else.
Personally, I found that by eating low-carb every day, my workout performance started to decline. So I tried eating carbs once a week, and that helped a little. Now I eat them almost every evening, but only in the evening. One to two low-carb meals during the day, and one higher-carb meal at night has been a perfect plan for me.
I am a study of one. You are too. The only way you’ll learn what works for you, is to pick your plan, and stick with it for several months. If it doesn’t work, try something else. If it does, stay with it.
When you find what works best for you, though, don’t assume it will work best for everyone.
[i] Wang CCL, Adochio RL, Leitner JW, et al. Acute effects of different diet compositions on skeletal muscle insulin signaling in obese individuals during caloric restriction. Metabolism. 2013;62(4):595-603
[ii] Gadgil MD, Appel LJ, Yeung E, et al. The Effects of Carbohydrate, Unsaturated Fat, and Protein Intake on Measures of Insulin Sensitivity. Diabetes Care. 2013;36:1132-1137
[iii] Hu T, Mills KT, Demanelis K, et al. Effects of Low-Carbohydrate Diets Versus Low-Fat Diets on Metabolic Risk Factors: A Meta-Analysis of Randomized Controlled Clinical Trials. Am J Epidemiol. 2012;176(Suppl):S44-S54
[iv] Jonasson L, Gullbrand H, Lundberg AK, Nyström F. Advice to follow a low-carbohydrate diet has a favorable impact on low-grade inflammation in type 2 diabetes compared with advice to follow a low-fat diet. Ann of Med. 2014;46(3)
[v] Gower BA, Goss AM. A Low-Carbohydrate, Higher-Fat Diet Reduces Abdominal Fat and Increases Insulin Sensitivity in Adults at Risk of Type 2 Diabetes. J Nutr. 2015;145(1)177S-183S
[vi] Ogden LG, Foster GD, Klein S, et al. Comparative Effects of Low-Carbohydrate High Protein Versus Low-Fat Diets on the Kidney. Clin J Am Soc Nephrol. 2012;7(7):1103-1111
[vii] Paoli A, Rubini A, Volek JS, Grimaldi KA. Beyond weight loss: a review of the therapeutic uses of very-low-carbohydrate (ketogenic) diets. Eur J Clin Nutr. 2013;67:789-796
[viii] Fine EJ, Feinman D. Insulin carbohydrate restriction, metabolic syndrome and cancer. Expert Rev. Endocrinol. Metab. 2014;9(6)
[ix] Lane AR, Duke JW, Hackney AC. Influence of dietary carbohydrate intake on the free testosterone:cortisol ratio responses in short-term intensive exercise training. Eur J Appl Physiol. 2010;108(6):1125-31
[x] Bisschop PH, Sauerwein HP, Endert E, Romijn JA. Isocaloric carbohydrate deprivation induces protein catabolism despite a low T3-syndrome in healthy men. Clin Endocinol. 2001;54(1):75-80