Clinical & PICO Question:

20-year-old female with BMI of 36.2 and PMHx of pre-diabetes presents to the office for her annual check-up. During patient education concerning exercise and a diet plan, she asked about the ketogenic diet. Patient wanted to know if the ketogenic diet help lower her HbA1C. The ketogenic diet is composed of a low carbohydrate and/or high fat diet.

For adults with diabetes type 2, how much of an impact does the ketogenic diet have on HbA1c in comparison to traditional diets?

PICO Search Elements:

P	I	C	O
Adults	Ketogenic diet	Low calorie diet	HbA1c
Diabetes	Keto diet	Low fat diet	Hemoglobin A1c
Diabetes Mellitus	Low carbohydrate diet		Fasting blood glucose
Diabetes Mellitus Type II	Very low carbohydrate diet
Diabetes Type 2	Low carbohydrate and high fat diet

 

Search Strategy:

TripDatabase:

(diabetics)(ketogenic diet)(low calorie diet)(hba1c)-> 46 results

PubMed:

ketogenic diet hba1c-> 12 results

diabetes type 2 ketogenic diet hba1c-> 7 results

diabetic ketogenic diet hba1c-> 3 results

Cochrane:

diabetes mellitus type 2 ketogenic diet-> 2 results

 

Results found:

1. Effect of low-calorie versus low-carbohydrate ketogenic diet in type 2 diabetes

Talib A. Hussain M.B., Ch.B., R.C.G.P., Thazhumpal C. Mathew M.Sc., Ph.D., et al. Effect of low-calorie versus low-carbohydrate ketogenic diet in type 2 diabetes.Nutrition. 2012; 28: 1016-1021. doi:10.1016/j.nut.2012.01.016.

https://www.ncbi.nlm.nih.gov/pubmed/22673594

http://sci-hub.tw/https://doi.org/10.1016/j.nut.2012.01.016#

OBJECTIVE: Effective diabetic management requires reasonable weight control. Previous studies from our laboratory have shown the beneficial effects of a low-carbohydrate ketogenic diet (LCKD)in patients with type 2 diabetes after its long-term administration. Furthermore, it favorably alters the cardiac risk factors even in hyperlipidemic obese subjects. These studies have indicated that, in addition to decreasing body weight and improving glycemia, LCKD can be effective in decreasing antidiabetic medication dosage. Similar to the LCKD, the conventional low-calorie, high nutritional value diet is also used for weight loss. The purpose of this study was to understand the beneficial effects of LCKD compared with the low-calorie diet (LCD) in improving glycemia. METHODS: Three hundred and sixty-three overweight and obese participants were recruited from the Al-Shaab Clinic for a 24-wk diet intervention trial; 102 of them had type 2 diabetes. The participants were advised to choose LCD or LCKD, depending on their preference. Body weight, body mass index, changes in waist circumference, blood glucose level, changes in hemoglobin and glycosylated hemoglobin, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, uric acid, urea and creatinine were determined before and at 4, 8, 12, 16, 20, and 24 wk after the administration of the LCD or LCKD. The initial dose of some antidiabetic medications was decreased to half and some were discontinued at the beginning of the dietary program in the LCKD group. Dietary counseling and further medication adjustment were done on a biweekly basis. RESULTS: The LCD and LCKD had beneficial effects on all the parameters examined.Interestingly, these changes were more significant in subjects who were on the LCKD as compared with those on the LCD. Changes in the level of creatinine were not statistically significant. CONCLUSION: This study shows the beneficial effects of a ketogenic diet over the conventional LCDin obese diabetic subjects. The ketogenic diet appears to improve glycemic control.Therefore, diabetic patients on a ketogenic diet should be under strict medical supervision because the LCKD can significantly lower blood glucose levels.

2. Influence of Fat and Carbohydrate Proportions on the Metabolic Profile in Patients With Type 2 Diabetes: A Meta-Analysis

Kodama, S., Saito, K., Tanaka, S., et. al. (2009). Influence of Fat and Carbohydrate Proportions on the Metabolic Profile in Patients With Type 2 Diabetes: A Meta-Analysis. Diabetes Care, 32(5), 959–965. doi:10.2337/dc08-1716

http://www.crd.york.ac.uk/CRDWeb/ShowRecord.asp?AccessionNumber=12009105859

https://sci-hub.tw/10.2337/DC08-1716

OBJECTIVE — The effects of dietary macronutrient composition on metabolic profiles in patients with type 2 diabetes have been inconsistent. This meta-analysisaimed to elucidate the effect of replacing dietary fat with carbohydrate on glucose and lipid parameters in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS — We searched for randomized trials that investigated the effects of two kinds of prescribed diets (a low-fat, high-carbohydrate [LFHC] diet and a high-fat, low-carbohydrate [HFLC] diet); in these studies, energy and protein intake did not differ significantly between the two dietary groups. Nineteen studies that included 306 patients met our inclusion criteria. Median diet composition of carbohydrate/fat in the LFHC and HFLC diets was 58%/24% and 40%/40%, respectively. RESULTS — Changes in values for A1C, fasting plasma glucose (FPG), and total and LDL cholesterol did not differ significantly between the LFHC and HFLC groups. However, the LFHC diet significantly increased fasting insulin and triglycerides by 8% (P 􏰀 0.02) and 13% (P 􏰁 0.001),respectively, and lowered HDL cholesterol by 6% (P 􏰁 0.001) compared with the HFLC diet. There were positive associations among the magnitude of changes in FPG, fasting insulin, and triglycerides for the diets analyzed. However, stratified analysis indicated that the increase in triglycerides was insignificant when accompanied by energy intake restriction. CONCLUSIONS — Our findings suggested that replacing fat with carbohydrate could de- teriorate insulin resistance while the adverse effect on triglycerides from the LFHC diet could be avoided by restricting energy intaketo a degree sufficient for the attainment of weight reduction.

3. Very-low-carbohydrate ketogenic diet v. low-fat diet for long-term weight loss: a meta-analysis of randomised controlled trials

Bueno NB, de Melo ISV, de Oliveira SL, da Rocha Ataide T. Very-low-carbohydrate ketogenic diet v. low-fat diet for long-term weight loss: a meta-analysis of randomised controlled trials. British Journal of Nutrition. 2013;110(7):1178-1187. doi:10.1017/S0007114513000548. https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/verylowcarbohydrate-ketogenic-diet-v-lowfat-diet-for-longterm-weight-loss-a-metaanalysis-of-randomised-controlled-trials/6FD9F975BAFF1D46F84C8BA9CE860783

Supplementary Material:https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/verylowcarbohydrate-ketogenic-diet-v-lowfat-diet-for-longterm-weight-loss-a-metaanalysis-of-randomised-controlled-trials/6FD9F975BAFF1D46F84C8BA9CE860783#fndtn-supplementary-materials

The role of very-low-carbohydrate ketogenic diets (VLCKD) in the long-term management of obesity is not well established. The present meta-analysis aimed to investigate whether individuals assigned to a VLCKD (i.e. a diet with no more than 50 g carbohydrates/d) achieve better long-term body weight and cardiovascular risk factor management when compared with individuals assigned to a conventional low-fat diet (LFD; i.e. a restricted-energy diet with less than 30% of energy from fat). Through August 2012, MEDLINE, CENTRAL, ScienceDirect, Scopus, LILACS, SciELO, ClinicalTrials.gov and grey literature databases were searched, using no date or language restrictions, for randomized controlled trials that assigned adults to a VLCKD or a LFD, with 12 months or more of follow-up. The primary outcome was bodyweight. The secondary outcomes were TAG (triacylglycerol), HDL-cholesterol (HDL-C), LDL-cholesterol (LDL-C), systolic and diastolic blood pressure, glucose, insulin, HbA1c and C-reactive protein levels. A total of thirteen studiesmet the inclusion/exclusion criteria. In the overall analysis, five outcomes revealed significant results. Individuals assigned to a VLCKD showed decreased body weight (weighted mean difference 20·91 (95% CI 21·65, 20·17) kg, 1415 patients), TAG (weighted mean difference 20·18 (95% CI 20·27, 20·08) mmol/l, 1258 patients) and diastolic blood pressure (weighted mean difference 21·43 (95% CI 22·49, 20·37) mmHg, 1298 patients) while increased HDL-C(weighted mean difference 0·09 (95% CI 0·06, 0·12) mmol/l, 1257 patients) and LDL-C (weighted mean difference 0·12 (95% CI 0·04,0·2) mmol/l, 1255 patients). Individuals assigned to a VLCKD achieve a greater weight loss than those assigned to a LFD in the longterm; hence, a VLCKD may be an alternative tool against obesity.

 

4. Comparison of low- and high-carbohydrate diets for type 2 diabetes management: a randomized trial

Tay, J., Luscombe-Marsh, N. D., Thompson, C. H., et. al. Comparison of low- and high-carbohydrate diets for type 2 diabetes management: a randomized trial. The American Journal of Clinical Nutrition. 2015. 102(4), 780–790. doi:10.3945/ajcn.115.112581

https://www.ncbi.nlm.nih.gov/pubmed/26224300

https://academic.oup.com/ajcn/article/102/4/780/4564662

BACKGROUND: Few well-controlled studies have comprehensively examined the effects of very-low-carbohydrate diets on type 2diabetes (T2D).OBJECTIVE: We compared the effects of a very-low-carbohydrate, high-unsaturated fat, low-saturated fat (LC) dietwith a high-carbohydrate, low-fat (HC)diet on glycemic controland cardiovascular disease risk factors in T2D after 52 wk.DESIGN: In this randomized controlled trialthat was conducted in an outpatient research clinic, 115 obese adults with T2D[mean ± SD age: 58 ± 7 y; body mass index (in kg/m(2)): 34.6 ± 4.3; glycated hemoglobin (HbA1c): 7.3 ± 1.1%; duration of diabetes: 8 ± 6 y] were randomly assigned to consume either a hypocaloric LC diet [14% of energy as carbohydrate (carbohydrate <50 g/d), 28% of energy as protein, and 58% of energy as fat (<10% saturated fat)] or an energy-matched HC diet [53% of energy as carbohydrate, 17% of energy as protein, and 30% of energy as fat (<10% saturated fat)] combined with supervised aerobic and resistance exercise (60 min; 3 d/wk).Outcomes were glycemic control assessed with use of measurements of HbA1c, fasting blood glucose, glycemic variability assessed with use of 48-h continuous glucose monitoring, diabetes medication, weight, blood pressure, and lipids assessed at baseline, 24, and 52 wk. RESULTS: Both groups achieved similar completion rates (LC diet: 71%; HC diet: 65%) and mean (95% CI) reductions in weight [LC diet: -9.8 kg (-11.7, -7.9 kg); HC diet: -10.1 kg (-12.0, -8.2 kg)], blood pressure [LC diet: -7.1 (-10.6, -3.7)/-6.2 (-8.2, -4.1) mm Hg; HC diet: -5.8 (-9.4, -2.2)/-6.4 (-8.4, -4.3) mm Hg], HbA1c [LC diet: -1.0% (-1.2%, -0.7%); HC diet: -1.0% (-1.3%, -0.8%)], fasting glucose [LC diet: -0.7 mmol/L (-1.3, -0.1 mmol/L); HC diet: -1.5 mmol/L (-2.1, -0.8 mmol/L)], and LDL cholesterol [LC diet: -0.1 mmol/L (-0.3, 0.1 mmol/L); HC diet: -0.2 mmol/L (-0.4, 0.03 mmol/L)] (P-diet effect ≥ 0.10). Compared with the HC-diet group, the LC-diet group achieved greater mean (95% CI) reductions in the diabetes medication score [LC diet: -0.5 arbitrary units (-0.7, -0.4 arbitrary units); HC diet: -0.2 arbitrary units (-0.4, -0.06 arbitrary units); P = 0.02], glycemic variability assessed by measuring the continuous overall net glycemic action-1 [LC diet: -0.5 mmol/L (-0.6, -0.3 mmol/L); HC diet: -0.05 mmol/L (-0.2, -0.1 mmol/L); P = 0.003], and triglycerides [LC diet: -0.4 mmol/L (-0.5, -0.2mmol/L); HC diet: -0.01 mmol/L (-0.2, 0.2 mmol/L); P = 0.001] and greater mean (95% CI) increases in HDL cholesterol [LC diet: 0.1 mmol/L (0.1, 0.2 mmol/L); HC diet: 0.06 mmol/L (-0.01, 0.1 mmol/L); P = 0.002].CONCLUSIONS: Both diets achieved substantial weight loss and reduced HbA1c and fasting glucose. The LC diet, which was high in unsaturated fat and low in saturated fat, achieved greater improvements in the lipid profile, blood glucose stability, and reductions in diabetes medication requirements, suggesting an effective strategy for the optimization of T2D management. This trial was registered at www.anzctr.org.au as ACTRN12612000369820.

 

5. A non-calorie-restricted low-carbohydrate diet is effective as an alternative therapy for patients with type 2 diabetes

Yamada, Y., Uchida, J., Izumi, H., t. al. (2014). A Non-calorie-restricted Low-carbohydrate Diet is Effective as an Alternative Therapy for Patients with Type 2 Diabetes. Internal Medicine, 53(1), 13–19. doi:10.2169/internalmedicine.53.0861

https://www.ncbi.nlm.nih.gov/pubmed/24390522

http://sci-hub.tw/10.2169/internalmedicine.53.0861

OBJECTIVE: Although caloric restriction is a widely used intervention to reduce body weight and insulin resistance, many patients are unable to comply with such dietary therapy for long periods. The clinical effectiveness of low-carbohydrate diets was recently described in a position statement of Diabetes UK and a scientific review conducted by the American Diabetes Association. However, randomised trials of dietary interventions in Japanese patients with type 2 diabetes are scarce. Therefore, the aim of this study was to examine the effects of a non-calorie-restricted, low-carbohydrate diet in Japanese patients unable to adhere to a calorie-restricted diet.METHODS: The enrolled patients were randomly allocated to receive a conventional calorie-restricted dietor low-carbohydrate diet. The patients received consultations every two months from a registered dietician for six months. We compared the effects of the two dietary interventions on glycaemic control and metabolic profiles.RESULTS: The HbA1c levels decreased significantly from baseline to six months in the low-carbohydrate diet group (baseline 7.6±0.4%, six months 7.0±0.7%, p=0.03)but not in the calorie-restricted group (baseline 7.7±0.6%, six months 7.5±1.0%, n.s.), (between-group comparison, p=0.03). The patients in the former group also experienced improvements in their triglyceride levels, without experiencing any major adverse effects or a decline in the quality of life.CONCLUSION: Our findings suggest that a low-carbohydrate diet is effective in lowering the HbA1c and triglyceride levels in patients with type 2 diabetes who are unable to adhere to a calorie-restricted diet.

 

Summary of the Evidences:

Author (Date)	Level of Evidence	Sample/Setting (# of subjects/ studies)	Outcome(s) studied	Key Findings	Limitations and Biases
1. Talib A. Hussain M.B., Ch.B., R.C.G.P., Thazhumpal C. Mathew M.Sc., Ph.D., et al. (2012)   Effect of low-calorie versus low-carbohydrate ketogenic diet in type 2 diabetes	Applied nutritional investigation- Cohort Study	– 363 overweight and obese participants-24 week diet intervention trial – 102 of them had T2DM – Participants were advised to choose LCD (low calorie diet) or LCKD (low-carbohydrate ketogenic diet), depending on their preference; therefore NOT randomized or  evenly distributed – Diabetic LCD= 24 participants – Diabetic LCKD=  78 participants	– Body weight, body mass index, changes in waist circumference, blood glucose level, changes in hemoglobin and glycosylated hemoglobin, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, uric acid, urea, and creatinine	– LCD and LCKD had beneficial effects on all the studies outcomes. However, these changes were more significant in subjects who were on the LCKD (average glycosylated Hgb of 7.8mg/dl to 6.25mg/dl) as compared to those on the LCD (average glycosylated Hgb of 8.25mg/dl to 7.75mg/dl) (except for creatinine). – Effectiveness of LCKD was much greater (P<0.0001) in diabetic LCKD group (change of -1.55mg/dl) than the LCD group (change of   -0.5mg/dl) compared with initial week 1 and final week 24. – Therefore, HbA1c levels significantly decreased (3.1 times more) with the LCKD compared to the LCD in the diabetic group.	– Small study that was not randomized nor evenly distributed – Short duration – Further studies necessary to examine the optimal adjustments, such as diabetic medications, diuretic agents, avoidance of hypoglycemia and dehydration.
2. Kodama, S., Saito, K., Tanaka, S., et. al. (2009)   Influence of Fat and Carbohydrate Proportions on the Metabolic Profile in Patients With Type 2 Diabetes: A Meta-Analysis	Meta-Analysis of RCTs	– 19 RCT studies= 306 patients – RCTS investigated 2 kinds of prescribed diets a LFHC diet (low-fat, high-carbohydrate) and a HFLC diet (high-fat, low-carbohydrate) – 10/19 RCT studies analyzed A1c changes between LFHC and HFLC diets	– A1c, fasting plasma glucose, 2-hour postprandial glucose, fasting insulin, 2-hour postprandial fasting insulin, total cholesterol, triglycerides, HDL cholesterol, LDL cholesterol	– Changes in FPG and A1C did not differ between the two diets despite significant elevations in 2-h and fasting insulin with the LFHC diet – Overall -1.5% difference of A1C between the LFHC and HFLC diets – 95% CI (LFHC -5.3 to HFLC 2.3) – P <0.70	– Publication bias of Begg’s test (0.80) and Egger’s test (0.47) for A1c  statistics – Few studies investigated long-term effects (e.g., 􏰅2 months) of changing the proportions of carbohydrate and fat on metabolic profiles in patients with type 2 diabetes – Most studies provided insufficient data about baseline glucose and lipid levels, and few focused on black or Asian patients – Therefore, the current meta-analysis provides limited suggestions on identifying patients for whom a low-fat or low-carbohydrate diet is especially effective in terms of their circumstances or metabolic profiles
3. Bueno NB, de Melo ISV, de Oliveira SL, da Rocha Ataide T. (2013)   Very-low-carbohydrate ketogenic diet v. low-fat diet for long-term weight loss: a meta-analysis of randomised controlled trials	Systematic review with Meta- analysis of RCTs	– VLCKD (very-low carbohydrate ketogenic diet) – LFD (low-fat diet) – Searched for RCTs that assigned adults to a VLCKD or a LFD, with 12 months or more of follow-up – 13 RCTs met the criteria – 4 RCTs revealed results for HbA1c	– Primary outcome studied= bodyweight – Secondary outcomes= TAG (triacylglycerol), HDL-cholesterol (HDL-C), LDL-cholesterol (LDL-C), systolic and diastolic blood pressure, glucose, insulin, HbA1c and C-reactive protein levels	– HbA1c, fasting blood glucose, insulin, and C-reactive protein analyses were performed in <10 studies; thus, no sensitivity, subgroup, meta-regression and publication bias analyses were conducted nor did the analyses show statistically significant results – HbA1c analysis- 4 studies (319 patients) were assessed (weighted mean difference of HbA1c% in favor of the VLCKD -0.24% (95 % CI  0.55, 0.06) P= 0.12; I 2= 0.0%,P= 0.59) (These statistics can be identified in the supplemental attachment of the study)	– The Cochrane risk of bias tool was used in the present meta-analysis. – Only blood risk factors were assessed, neglecting important pathological markers such as hepatic lipid infiltration, endothelial function, general cardio- vascular events, and renal function, which are important in assessing the safety of dietary therapies – Adherence to the VLCKD in the included studies was low – Upcoming trials should focus on dietary adherence, implementing measures to ensure that individuals adhere to the protocol, as was done by some of the included studies, permitting better investigation of the long-term effects of a VLCKD
4. Tay, J., Luscombe-Marsh, N. D., Thompson, C. H., et. al. (2015)   Comparison of low- and high-carbohydrate diets for type 2 diabetes management: a randomized trial	Randomized control trial	– Very-low-carbohydrate, high-unsaturated fat, low-saturated fat (LC) diet vs high-carbohydrate, low-fat (HC) diet on glycemic control and cardiovascular disease risk factors in T2D after 52 weeks – 115 obese patients with T2D – Combined with supervised aerobic and resistance exercise for 60 minutes/ 3 days a week	– Outcomes were glycemic control assessed with use of measurements of HbA1c, fasting blood glucose, glycemic variability assessed with use of 48-h continuous glucose monitoring, diabetes medication, weight, blood pressure, and lipids assessed at baseline, 24, and 52 wk.	– HbA1c- LC diet= -1.0% (-1.2%, -0.7%) HC diet= -1.0% (-1.3%, -0.8%)   – Both diets achieved equal yet substantial weight loss and reduced HbA1c and fasting glucose – The LC diet, achieved greater improvements in the lipid profile (-0.4mmol/L compared to -0.01mmol/L change with HC diet), blood glucose stability, and reductions in diabetes medication requirements [MES (medication effect score) reduction >50% of 17% compared to 10% reduction by HC diet] , suggesting an effective strategy for the optimization of T2D management	– In contrast to meta-analyses of previous trials that reported improvements in LDL cholesterol favoring HC compared with very-low-carbohydrate diets, the current study showed both diets achieved comparable LDL-cholesterol reductions. – Individuals with uncontrolled diabetes at baseline (HbA1c 11.0%) were excluded from the study, and whether these results are generalizable to these patients requires confirmation
5. Yamada, Y., Uchida, J., Izumi, H., t. al. (2014)   A Non-calorie-restricted Low-carbohydrate Diet is Effective as an Alternative Therapy for Patients with Type 2 Diabetes	Randomised, open-label trial	– Enrolled patients were randomly allocated to receive a conventional calorie-restricted diet or low-carbohydrate diet for 6 months – 24 participants (12 participants per group)	– Compared the effects of the two dietary interventions on glycemic control and metabolic profiles	– HbA1c levels decreased significantly from baseline to 6 months in the low-carbohydrate diet group (baseline- 7.6±0.4%-> 6 months- 7.0±0.7%, p=0.03) – Calorie-restricted group (baseline- 7.7±0.6%-> 6months 7.5±1.0%) -Between-group comparison, p=0.03	– Number of subjects enrolled was too small to detect significant differences in the between-group and within-group comparisons – 6 month study- Improvements in the HbA1c levels and body weight observed at 6 months in the study may be attenuated over a longer observation period

 

Conclusion(s):

1. Talib (2012)-There was an impressive improvement in HbA1c secondary to the LCKD (average reduced glycosylated Hgb difference of 1.55mg/dl) as compared to those on the LCD (average glycosylated Hgb difference of 0.5mg/dl). That is a change in reduction 3.1 times more with the LCKD compared to the LCD in the diabetic group.The improvement in glycemic control occurred after the diabetic medications had been decreased substantially in participants using the LCKD program to avoid hypoglycemia.
2. (Kodama 2009)-Replacement of dietary fat with carbohydrate (LFHC diet) is not recommended for improvement of insulin resistance in patients with type 2 diabetes under conditions whereby total energy and protein intake and the content of carbohydrate are similar and the proportion of carbohydrate to total energy is <30%. Overall there was a -1.5% insignificant difference of A1c between LFHC and HFLC diets.
3. Bueno (2013)-Individuals assigned to a VLCKD (very low carb keto diet) achieve significantly greater long-term reductions in body weight, diastolic blood pressure and TAG, as well as greater LDL and HDL increases when compared with individuals assigned to a LFD. Since only 4 of the 13 RCTs had statistics pertaining to HA1c, none of the analyses showed significant results. There was aweighted mean difference of HbA1c% in favor of the VLCKD -0.24%, which was of little significance.
4. Tay (2015)-Both the LC (low carb high fat) and HC (high carb and low fat) diets produced comparable weight loss (both equally -1.0% HbA1c% decrease) and improvements in HbA1c and several CVD risk markers. The results suggest that LC diets with high-unsaturated and low-saturated fat contents may be advantageous for T2D management over the long term.
5. Yamada (2014)-Non-calorie-restricted, low- carbohydrate diet is effective (baseline- 7.6±0.4%-> 6 months- 7.0±0.7%, p=0.03) in lowering the HbA1c and TG levels and is safe as an alternative therapy for patients with type 2 diabetes.

Overarching conclusion:As per the 5 conclusions, there is some disagreement as to whether or not the ketogenic diet (a low carb and high fat diet) is has a significant effect on HbA1c compared to the popular low calorie or low fat diets. There is major variance between the studies such as some followed very low carb diets, some added the variance of high or low fat to the diets, and one added the variability of exercise in addition to the diets. Due to such discrepancies, it is necessary to establish studies that are more comparable to each other in order to formulate a more accurate conclusion.

 

Clinical Bottom Line:

The United States is used as a common punch line for jokes concerning the high obesity rate. Due to the high rate of obesity within the country, every few years or so there is a “new and improved” or “revolutionary” diet to help the public lose weight. Losing weight is usually of high concern, as obesity can lead to a high risk of diabetes, heart disease, and possibly cancer. The ketogenic diet is of high popularity, most popularly advertised by celebrities, but is of low familiarity of the risks and benefits besides weight loss and BMIs. As per the studies mentioned in this critically appraised topic, the ketogenic diet (a low carbohydrate with high fat diet) appears to have a positive effect in lowering the HbA1c in patients with type 2 diabetes with some risks of hypoglycemia and increase in total cholesterol. There was a variety in the level of evidence in the 5 studies for this Critically Appraised Topic. Each study provided a different level of evidence towards the clinical bottom line. Although the studies were of high levels of evidence such as meta-analyses, systematic reviews, and RCTS, there were major limitations such as short durations, small populations, or questionable adherence to the diets. Talib (2012), Tay (2015), and Yamada (2014) had small study groups, which lower the weight of their evidence on the clinical bottom line. Although small study groups, all 3 studies acknowledge their limitations and still support their conclusions; low carbohydrate diets have a more noteworthy effect on lowering HbA1c compared to the competing group. There are also some major side effects to the ketogenic diet such as hypoglycemia and increase in total cholesterol due to the low carb intake and high fat intake. All 5 studies mentioned a common recurrence of hypoglycemia and hyperlipidemia when the patients followed low carbohydrate and high fat diet plans, which can cause an increase in cardiovascular risk factors. Although there is strong mention of low carbohydrate ketogenic diets decreasing HbA1c, there is poor statistical significance compared to the contrasting diet in the ketogenic diet having a significant impact in lowering HbA1c. Patients do have significant weight loss, decrease in BMIs, and decrease in HbA1cs. However, there is no meaningful or statistical difference in the decrease in HbA1c between a low carbohydrate high fat diet compared to a high carbohydrate and low fat diet. Further studies are necessary with larger study groups over a longer period of time with diet plans that are more alike, which would indicate toward a more precise conclusion.