- A recent study investigated the effects of a low-carbohydrate ketogenic diet on adults with treatment-resistant depression.
- Treatment-resistant depression occurs when someone’s symptoms do not improve after trying at least two different antidepressants.
- The participants who followed a ketogenic diet experienced greater improvement in their depressive symptoms. However, as this difference diminished by the 12-week follow-up, the effects may be short-lived.
Researchers from the United Kingdom recently studied whether a ketogenic (keto) diet, low in carbs, could help adults with treatment-resistant depression.
Depression is
Doctors describe depression as “treatment-resistant” when someone does not see an improvement in their symptoms after trying at least two different antidepressants.
Prior research shows that food choices may impact mood, and the researchers in the new study wanted to find out whether a keto diet could help with treatment-resistant depression symptoms.
The trial included 88 participants who were randomly assigned to follow a keto diet or a control diet for 6 weeks. Both groups had improvements in depression symptoms, but the keto group had a slightly greater improvement at 6 weeks.
However, the difference was reduced at the 12-week follow-up, leading the researchers to wonder whether the benefits from the keto diet are more of a short-term effect.
The findings appear in the journal
The goal of a ketogenic diet is to put the body in ketosis and burn fat by reducing carbs and increasing healthy fats. Ketosis occurs when the liver breaks down fat into ketone bodies, which then serve as fuel for the body and brain.
Nutrition can impact the body in many ways and can cause inflammation and even impact brain functioning.
They recruited 88 adults ages 18 to 65 with treatment-resistant depression. Half of the participants followed a keto diet, and the other half in the control group followed a phytochemical or “phyto” diet.
The researchers provided the keto group with prepared foods that were 30 grams (g) of carbs or less per day.
The phyto group participants — which made up the control group — used vouchers to purchase fruits and vegetables with the goal of adding one extra serving, plus they replaced saturated fats with unsaturated fats.
The researchers provided coaching and support to both groups. Additionally, they made sure all participants ate enough to maintain their current weight to avoid mood improvements being attributed to weight loss rather than food.
The scientists used the Patient Health Questionnaire (PHQ-9) to monitor depression symptoms and also monitored anxiety and other mental health issues during the 6 weeks.
They hoped to see a 5-point improvement on the PHQ-9 in the keto group versus the phyto group, which would count as being “clinically important.”
At the end of the 6-week period, the participants were allowed to either continue following their diet plans or go back to their regular food choices. The researchers followed up with the participants at 12 weeks.
At the 6-week check-in, both groups saw improvements in depression symptoms.
The keto group saw the greatest improvement with their depression scores dropping by about 10 points compared to the phyto group’s drop of about 8 points.
Additionally, some participants achieved depression remission at 6 weeks — 25% in the keto group versus 9% in the phyto group.
At the 12-week follow-up, half of the participants in the keto group had stopped following the diet. The remaining participants in this group were only following the keto diet some of the time, and about 9% followed it nearly every day.
In the phyto group, 5% had stopped, two-thirds were following the phyto diet some of the time, and 25% nearly every day.
Depression declined slightly in both groups, while remission rates stayed about the same. The researchers did not find an overall improvement in the other mental health areas.
A subgroup finding was that people with more severe depression at the start of the trial seemed to benefit more from the keto diet than those with moderately severe symptoms.
Of the participants with the highest depression scores, the keto group improved more than the comparison group.
Overall, while the study shows that the keto diet may help in the short term, the drop from 6 to 12 weeks suggests that the benefits may not be long-term.
The researchers said the findings were clinically uncertain since the drop was not five points more for the keto group compared to the phyto group, and future studies are needed.
Min Gao, PhD, an epidemiologist and health behavior scientist affiliated with Oxford University and lead study author, spoke with Medical News Today about the research findings.
“The key takeaway is that a ketogenic diet may offer a small short-term benefit for some people with severe depression, but it’s not a cure, it’s difficult to stick to, and it doesn’t change current treatment recommendations. This is promising early evidence, but it comes with clear limits.”
– Min Gao, PhD
Gao discussed that the next step in this line of research is to figure out which people the keto diet helps the most and how to “make any benefit easier and safer to achieve.”
Zishan Khan, MD, a board-certified psychiatrist and Regional Medical Director with Mindpath Health, who was not involved in this research, spoke with MNT about the trial.
Khan described it as a “well-designed, carefully conducted early trial” that shows that a ketogenic diet may have a “modest” short-term antidepressant effect as an addition to treatment.
“First, this study should be seen as proof‑of‑concept that diet, including a ketogenic pattern, can influence mood even in people who have not responded well to medications, but it is not evidence that ketogenic diets are a replacement for established treatments,” he cautioned.
He also emphasized that all participants continued their antidepressants during the trial and said anyone considering this diet should do so under a physician’s care.
Khan also touched on the 2-point advantage on the PHQ-9 that the keto diet had.
“For a population with treatment‑resistant depression, a roughly 2‑point mean advantage on the PHQ‑9 over an already active comparator is not trivial, but it is also not a game‑changer on its own,” Khan concluded.
