The net is full of misinformation about hormonal acne, everything from useless supplements to dubious cleanses. However, science consistently shows that dietary changes can significantly reduce the hormones known to cause acne. Proper dietary changes, that it. One choice that can make a real difference is whether you fill your plate with carbohydrates or fat. In this post I’ll explain how the ratio of carbohydrates to fat in your diet affects hormone levels, and give you simple and easy to follow recommendations.
Carbohydrates vs. fat studies
A very recent paper published in the journal Clinical Endocrinology put women with PCOS on two dietary regimens. The hormonal profile of PCOS is quite similar to that of female adult acne, so it’s a good proxy group to use (many more diet studies are done with PCOS than with acne patients). Here’s the macronutrient composition for the two diet groups.
- 55% carbs
- 27% fat
- 18% protein
Reduced carb diet:
- 41% carbs
- 40% fat
- 19% protein
The study was so-called crossover design, meaning that the participants started first with one diet and later on switched to the other diet (with a washout period between the two diets). There was no difference in the overall caloric intake between the diets. These graphs show the change in relevant measurements for both groups: Source: Favourable metabolic effects of a eucaloric lower-carbohydrate diet in women with PCOS.
STD refers to standard diet and lower-CHO refers to the reduced carbohydrate diet group. The stars refer to levels of statistical significance between the two groups, the more stars the higher the statistical significance level. As you can see, moderately reducing carbohydrate intake improved all the acne-relevant hormones. The most notable changes were (I calculated these from the data in the paper):
- 25% reduction in testosterone in the lower-CHO group vs. 1% increase in the STD group.
- 23% increase in the 1st phase insulin response (PhiD) in the lower-CHO group vs. 2% increase in the STD group. Poor 1st phase insulin response is one of the first signs of blood sugar problems. As a result of poor 1st phase response post-meal blood sugar levels increase too high and overtime this can cause further insulin resistance damage to pancreas.
- 26% lower fasting insulin in the lower-CHO group vs. 22% decrease in the STD group.
In a nutshell, reducing carbohydrate intake reduced the levels of many hormones known to affect acne.
One caveat about the study. The lower-CHO group not only ate less carbohydrates, but the glycemic index of those carbohydrates vas also little bit lower (average GI 50 vs. 60). I’m sure this reduction in GI was partly responsible for the beneficial effects in the lower-CHO group. This is of course just one study, and we should never hang our hats on a single study. But I featured this study because I feel it’s fairly representative of the evidence-base as a whole, as a recent systematic review of dietary composition studies for PCOS shows:
There were subtle differences between diets, with greater weight loss for a monounsaturated fat-enriched diet; improved menstrual regularity for low-glycemic index diet; increased free androgen index for a high-carbohydrate diet [bad for acne]; greater reductions in insulin resistance, fibrinogen, total, and high-density lipoprotein cholesterol for a low-carbohydrate or low-glycemic index diet; improved quality of life for a low-glycemic index diet; and improved depression and self-esteem for a high protein diet.
Another systemic review of fat vs. carbohydrates in insulin resistance concludes:
There has been much debate over whether the recent increase in obesity and obesity-related disease is relevant to the current advice that has favored high-carbohydrate diets. The pendulum is now swinging in favor of fat as reflected by current dietary guidelines, in many ways driven by the allure of olive oil and the health attributes of the Mediterranean diet. Nevertheless, as more emphasis is placed on the nature of the carbohydrates in the diet, its fiber content and glycemic index, the case for certain types of carbohydrates again becomes more compelling.
Systemic reviews are papers that look at all the published studies on a given topic and try to derive a conclusion based on looking at all the available evidence. A well-conducted systemic review is considered to be the most compelling form of scientific evidence.
Food quality over macronutrient composition
If that last quote didn’t ring to you as an unconditional endorsement of fat over carbohydrates, well, that’s because it isn’t. While both of these papers mentioned that replacing a portion of carbohydrates with fat usually reduced insulin and androgen levels, both also mention that food quality is far more important than macronutrient composition. So your first order of priority should be to:
- Replace bad carbs (i.e. high glycemic index, low fiber) with good carbs (low GI, high fiber)
- Replace bad fats (i.e. trans fats, processed fats and possibly animal-derived saturated fats) with good fats (MUFA and plant-derived, unprocessed fats)
People with insulin resistance or other blood sugar problems, probably also benefit from moderate carbohydrate restriction as it reduces insulin load in your body. However, reducing carbohydrates too much can also cause problems. There’s some degree of competitive inhibition between fat and glucose (sugar) utilization. When your body burns fat it reduces burning of glucose and vice versa. This means that if you reduce carb intake too much, you train your body to burn more fat. So the next time you eat carbohydrates your body “doesn’t know what to do with them”, resulting in abnormally high blood sugar and insulin levels.
It therefore appears that an adequate intake of carbohydrate is required for normal glucose tolerance
Why fat reduces hormonal acne better than carbohydrates
Other studies shed some light on why fat reduces hormonal acne more than carbohydrates. Studies show that testosterone levels drop shortly after a meal, but also that meal composition affects post-prandial (post-meal) testosterone level as follows:
- High-fat meals suppress testosterone (T) levels longer than high-carb meals
- Eating animal fats results in less suppression of T than plant fats, i.e. T levels are higher following a meal of animal fat than a meal of plant-based fats
There’s also the fact that eating fat doesn’t cause an increase in insulin or blood sugar levels. Insulin level is especially important as insulin can stimulate the liver to release androgen hormones (DHEAS, a precursor to T and other androgens) and make your skin more sensitive to androgens.
Take-away and recommendations
Science shows that replacing some carbohydrates with fat can reduces hormones known to cause acne. In women with PCOS moderately restricting carbohydrates resulted in significant reductions in testosterone and insulin levels. That said, food quality triumphs over macronutrient composition, and simply improving the quality of the carbohydrates and fats in your diet affects your hormone levels more than tweaking carbs:fat ratio. Here are some simple science-based recommendations:
- Replace high GI carbs with low GI and fiber-rich carbohydrates (assuming fiber doesn’t cause gut problems for you).
- Get rid of trans-fats and other processed fats from your diet. Emphasize unprocessed fats mostly from plant sources (MUFAs in olive oils and nuts and seeds). Data on animal fats is still somewhat unclear; there’s no need to overtly restrict animal fats, but I also wouldn’t gobble them as health food.
- People with insulin resistance can also benefit from moderately restricting carbohydrates, perhaps to 40 to 45% of total caloric intake with fat bringing in another 40% of your calories. Restricting carbohydrates too much can also cause insulin resistance and cause problems if/when you eat them.
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