Recent research published in the Journal of Psychiatric Research has shed new light on the impact of low-carbohydrate diets on depression, revealing that not all low-carb approaches are created equal when it comes to mental health. The study found that adults who adhered to low-carb diets rich in plant-based proteins, unsaturated fats, and minimal refined carbohydrates were significantly less likely to report symptoms of depression. However, low-carb diets heavy in animal proteins and saturated fats did not confer the same mental health benefits, underlining the critical importance of diet quality — not just macronutrient ratios — for psychological well-being (PsyPost).
For Thai readers, where dietary trends often skew toward either traditional rice-rich meals or imported high-protein, low-carb regimens, these findings are particularly relevant. The study’s insights suggest that how we structure our eating patterns may play a role not only in our physical health, but also our mental resilience and mood — an urgent issue as Thailand, like much of the world, grapples with rising rates of depression.
The cross-sectional study, conducted by researchers in China and based on data from nearly 29,000 U.S. adults participating in the National Health and Nutrition Examination Survey (NHANES) from 2005-2018, represents one of the largest analyses to date on this topic. Participants’ diets were categorized using three scoring systems: an overall low-carbohydrate diet score (OLCD), a healthy low-carbohydrate diet score (HLCD) focused on plant-based proteins and healthy fats, and an unhealthy low-carbohydrate diet score (ULCD) centered on animal proteins and unhealthy fats. Depression symptoms were assessed using the Patient Health Questionnaire-9 (PHQ-9), a standard screening tool for mood disorders.
Key results showed that those adhering most closely to the healthy low-carb pattern (HLCD) — characterized by less refined carbohydrate intake and higher consumption of plant proteins, legumes, nuts, vegetables, and healthy oils — were about 30% less likely to exhibit significant symptoms of depression compared to those with the lowest scores. By contrast, no significant benefit was observed among participants whose low-carb diets consisted mainly of red and processed meats, saturated fats, and excluded nutritious whole foods.
This distinction is crucial. While many people embrace low-carb diets for weight management, the research cautions that simply slashing carbohydrate intake is insufficient. What replaces those carbohydrates matters greatly. Swapping white rice or sugary snacks for fish, tofu, edamame, avocados, and whole grains appears far more beneficial to mood and overall well-being than loading up on fatty grilled meats and cheese.
The researchers took care to adjust for confounding variables such as age, sex, race, education, body mass index, smoking, alcohol use, physical activity, and existing chronic diseases. They also conducted “substitution analysis,” showing that replacing low-quality carbohydrates with plant-based proteins or even lean animal proteins led to fewer depression symptoms.
Expert commentators reviewing the study highlight possible mechanisms for these findings. Diets abundant in plant-based foods and unsaturated fats possess anti-inflammatory and antioxidant properties, potentially protecting the brain from oxidative stress. Nutrients such as B vitamins, folate, and tryptophan — often found in legumes, nuts, and leafy greens — are known to be critical for synthesizing serotonin, a neurotransmitter linked to feelings of happiness and calm (Harvard Health Publishing). In contrast, eating patterns high in saturated fats and sugars can promote inflammation, which has been tied to increased risk of depression (Psychiatric Times). Gut health and sleep quality, both strongly affected by diet, are also believed to play central roles in regulating mood.
Crucially, the study found that moderate adherence to a healthy low-carb diet was more beneficial than extreme restriction. This aligns with traditional Thai dietary wisdom, which often prizes moderation and variety. It also echoes recommendations from the World Health Organization that emphasize balanced eating patterns rich in fruits, vegetables, legumes, and healthy oils for both mental and physical health (WHO). For Thai readers, this may mean that “low-carb” doesn’t have to mean “no rice ever” — but rather, choosing brown rice in sensible portions alongside vegetables, fish, and tofu instead of deep-fried dishes or sugary drinks.
The analysis also found the association between healthy low-carb diets and fewer depression symptoms was consistent across all subgroups — regardless of age, gender, race, marital status, or lifestyle habits such as smoking or exercise. Even after accounting for the use of antidepressant medications, the main findings held steady.
Despite its strengths — notably the large and diverse survey sample and careful differentiation between healthy and unhealthy low-carb diets — the study has some limitations. Because it is cross-sectional, it cannot prove that diet changes cause improvements in depression; rather, it shows a strong correlation. It’s also possible that people suffering from depression may have different eating patterns as a consequence of their mental state. Additionally, participants’ dietary habits were self-reported based on just two days of recall, which may not reflect their usual intake patterns.
Experts and the study authors agree that more longitudinal research is needed to establish whether healthy low-carb diets can prevent depression or reduce symptoms over time. Clinical trials providing well-defined dietary interventions and using more accurate tracking methods would help identify the underlying biological mechanisms.
For Thailand, where depression has become a growing public health concern particularly among urban youth and working-age adults (Bangkok Post), these findings have practical relevance. The Thai Ministry of Public Health and various advocacy groups have already been promoting healthier eating habits, advocating for more vegetables, legumes like mung beans, tofu, and fish in daily meals. This new research supports the idea that what ends up on our plates is intricately linked not just to our waistlines, but also to our mood and even emotional resilience.
Traditionally, Thai cuisine provides many opportunities to follow a “healthy low-carb” pattern, especially with an abundance of dishes centered on vegetables, herbs, mushrooms, fermented fish, seafood, and plant proteins — such as “larb tofu,” “kang liang,” or “yum tua ploo.” However, the increasing popularity of Western-style fast food and processed snacks among Thai youth poses a risk. These foods tend to be high in trans fats, sugar, and simple carbohydrates, which—according to this latest research—could heighten depression risk if they displace more nutrient-dense options.
Looking to the future, the growing recognition of the food-mood connection is likely to influence dietary recommendations in Thailand. Schools, workplaces, and hospitals may place greater emphasis on offering plant-forward menus and mindfulness around food choices. Dietitians and mental health professionals may also begin collaborating more closely, using food as part of holistic strategies to manage and prevent depression, particularly among vulnerable groups.
For Thai readers considering a shift toward healthier low-carb eating, practical strategies include:
- Replacing white rice or noodles with brown rice, quinoa, or whole grains.
- Prioritizing dishes built around vegetables, legumes, and tofu rather than fatty meats.
- Choosing grilled or steamed fish over fried or processed meats.
- Incorporating healthy oils such as olive oil, sesame oil, or canola oil.
- Limiting sugary snacks and beverages, opting instead for seasonal fruits or homemade desserts in moderation.
- Preparing traditional Thai salads such as “som tam” with more raw vegetables and less added sugar or salt.
As with any dietary change, it’s wise to consult with healthcare professionals, including dietitians or nutritionists, to ensure nutritional needs are met — especially for those with existing health conditions.
Ultimately, this landmark study provides a reminder that the pathway to physical and mental health runs through the kitchen. By embracing Thailand’s rich culinary heritage and modern nutritional science, readers can nourish not only their bodies, but also their minds.
References:
- PsyPost – Low-carb diets linked to reduced depression symptoms — but there’s a catch
- Journal of Psychiatric Research – Plant-based low-carbohydrate diets and depression symptoms
- Harvard Health Publishing – Foods linked to better brainpower
- World Health Organization – Healthy diet
- Bangkok Post – Depression affects 2.9m Thais