Blood, sugar and metabolism

Shown to lower fasting glucose by about 10 mg/dL and HbA1c by about 0.6 points in adults.

Shown to lower HbA1c by about 0.6 points and lower fasting glucose in people with type 2 diabetes, with larger effects in poorer-quality trials.

Shown to lower body weight by about 1.1 kg over placebo after 12 to 16 weeks in overweight or obese adults, on low-quality evidence.

Shown to lower body weight by about 0.35 to 0.7 kg more than placebo in adults, a change that may not be clinically important.

Linked to 18% lower type 2 diabetes per daily serving of yogurt in pooled cohorts. Total dairy showed no link in one review and 3% lower risk in another.

Compared with one fewer serving a day [10]; 50 g a day less yogurt or 200 g a day less total dairy, in dose-response models [9]

Shown to lower LDL cholesterol about 18% more than placebo when taken alone, with ApoB about 16% lower, and to lower LDL further when added to a statin.

Compared with placebo [1][2]; a statin or fenofibrate alone [3][4]

Shown to lower fasting glucose by about 1 mmol/L and HbA1c by about 0.85% in people with diabetes, only at medium or high doses.

Shown to lower LDL cholesterol by about 0.33 mmol/L with about 10 g of psyllium a day in adults with or without high cholesterol.

Shown to lower triglycerides by about 15% in adults, more at higher doses.

Shown to lower homocysteine in adults with high levels, kidney disease or type 2 diabetes. In kidney disease, cardiovascular events did not fall.

Shown to give at least 50% pain relief to 38% on gabapentin against 21% on placebo, and to 31% on pregabalin 300 mg against 24%.

Shown to lower total cholesterol about 10 to 17 mg/dL and LDL about 6 to 9 mg/dL in adults, more in those with high cholesterol.

Shown to lower LDL cholesterol by about 10%, about 16 mg/dL, in adults and children. Changes were not significant in adults with insulin resistance.

Shown to lower LDL cholesterol slightly, about 2 mg/dL, and total cholesterol about 7 mg/dL in adults, with no HDL change.

Shown to lower body weight and fat mass slightly more than standard-protein diets, by about 0.6 to 0.9 kg of fat.

Compared with diets with less protein

Shown to lower gestational diabetes about 44% to 47% with myo-inositol in pregnant women. One trial in women with PCOS found no change in a combined outcome.

Shown to lower body weight against usual eating in adults, by about 1.6 kg in pooled trials, though one 12-week trial without other changes found no difference.

Compared with no intervention or a waiting list [1]; eating over 10 or more hours a day [4]; no restriction [7]; usual diets, and late time-restricted eating for the early-window result [8]; three structured meals a day [9]

Shown to raise ferritin in iron-deficient adults and athletes without anemia, most in those starting with very low ferritin.

Shown to produce about 1 to 3 kg more weight loss than comparison diets in adults, with the smallest gap in trials of a year or longer.

Compared with diets that did not restrict carbohydrates to the level of ketosis

Shown to lower triglycerides by about 0.2 to 0.3 mmol/L and raise HDL cholesterol more than comparison diets in adults.

Compared with diets that did not restrict carbohydrates to the level of ketosis

Shown in pooled studies to lower weight and insulin resistance in women with PCOS. Against other diets, the reviews disagreed on weight.

Compared with other diets [21]; low-calorie diets [22]; before the diet, in the same women [21][22][23]

Shown to lower blood phosphate, urea and parathyroid hormone in adults with chronic kidney disease on a protein-restricted diet.

Shown to lower body weight about 1.2 kg in adults, mostly with overweight or obesity. Body fat percentage did not change, and the effect shrank over time.

Shown to lower weight about 1.4 to 2.2 kg after treating hypothyroidism, in overt cases only. Weight did not change in subclinical hypothyroidism.

Shown to cut about 5.6 kg more weight than placebo over a year in adults with obesity, alongside diet and activity counseling. Adolescents also lost more.

Shown to produce about 1 kg more weight loss than balanced-carbohydrate or low-fat diets in adults with overweight, a gap a Cochrane review calls little to no difference.

Compared with balanced-carbohydrate diets [1]; low-fat diets [2]; no diet, and low-fat diets in the same network meta-analysis [3]; a healthy low-fat diet [4]; a calorie-restricted low-fat diet and a calorie-restricted Mediterranean diet [5]

Shown to lower LDL cholesterol slightly more than higher-fat and low-carbohydrate diets, by about 0.07 to 0.16 mmol/L.

Compared with diets with more fat

Shown to lower type 2 diabetes incidence about 31% in adults with raised blood sugar, less than the 58% from lifestyle change.

Shown to lower BMI slightly more than placebo in women with PCOS, by about 0.5 to 0.8 kg/m2, or about 3 kg of body weight.

Compared with placebo [34][31]; lifestyle change with or without placebo [33]

Shown to lower insulin resistance and fasting glucose slightly against placebo in women with PCOS. Added to lifestyle change, one review found no extra effect.

Compared with placebo [34][31]; lifestyle change with or without placebo [33]; combined oral contraceptive pills [35]

Shown to cut about 2.5 to 5 kg more weight than placebo over a year in adults with overweight or obesity, depending on the analysis.

Shown to raise blood NAD in adults, by 22 to 142% depending on dose. A rise in NAD measures uptake, not health.

Shown to raise blood NAD in adults, highest at 600 to 900 mg a day. A rise in NAD measures uptake, not health.

Shown to lower LDL cholesterol about 0.26 to 0.30 mmol/L against usual diets in adults with cardiometabolic risk factors.

Compared with control groups the source does not describe [1]; a usual or habitual Nordic diet, a usual Western diet or general healthy eating advice [2]; the participants' usual Western diet, in Swedish adults [3]; an average Nordic diet with the same calories [4]

Shown to lower LDL cholesterol by about 4.8 mg/dL per daily ounce of tree nuts, and by 10.2 mg/dL at about 67 g a day, along with ApoB.

Compared with control arms without nuts [4]; control diets the abstract does not describe [5]

Linked to 16% to 22% lower type 2 diabetes at higher olive oil intake, in two pooled analyses of cohorts.

Compared with the lowest intake category [8]; 25 g a day less, in a dose-response model [3]

Shown to cut weight about 11% on the top dose against 2% on placebo over 72 weeks in adults with obesity, alongside lifestyle intervention.

Shown to lower HbA1c about 1.2 to 1.9 points in adults with type 2 diabetes, more than placebo, oral semaglutide or dapagliflozin. Not US approved for diabetes.

Shown to cut about 2 to 3 kg more weight than placebo over a year, the smallest effect of five obesity drugs compared.

Shown to lower total and LDL cholesterol slightly, by about 0.3 mmol/L, with larger drops when more weight was lost.

Shown to produce about 2 to 3.5 kg more weight loss than comparison diets in adults, with the fat-loss lead not significant at 2 years in one trial.

Compared with control diets the source does not describe [1]; diets based on official recommendations, mostly higher in vegetables, whole grains and low-fat dairy [2]; control diets the source does not describe [3]; a diet following the Nordic Nutrition Recommendations [4]

Shown to lower total and LDL cholesterol and triglycerides more than comparison diets in adults, though some pooled results depended on single trials.

Compared with control diets the source does not describe [1], [3]; a diet following the Nordic Nutrition Recommendations [4]; a control group the source does not describe [5]

Shown to cut about 8 to 9 kg more weight than placebo over a year with phentermine-topiramate, rising with dose, alongside lifestyle programs.

Linked to 26% less type 2 diabetes at 150 minutes a week of moderate activity in pooled cohorts, with further but smaller drops at higher amounts.

Compared with inactive individuals [5]; the lowest activity group [6]; inactive people [3]; insufficiently active people [4]

Shown to lower triglycerides in pooled trials of aerobic training, with HDL cholesterol rising modestly in two reviews and not changing overall in a third.

Compared with control groups in randomized trials [8][9]; no exercise, or diet alone [10]

Shown to lower body weight by up to 25% at 80 weeks in adults with obesity without diabetes, against about 4% on placebo.

Shown to lower HbA1c by about 0.66 points more than placebo in adults with type 2 diabetes, and about as much as other diabetes drugs.

Shown to lower body weight by about 1.3 to 1.9 kg in trials, in adults with type 2 diabetes and in adults with overweight and no diabetes.

Linked to more type 2 diabetes with more sitting or TV time in pooled cohorts, with a steady rise and no threshold.

Compared with people with less sedentary time, with physical activity held equal [1]; each hour less of sitting or TV a day [3]; each 2 hours less of TV a day [6]

Shown to lower blood sugar and insulin after meals when long sitting was broken up with short activity breaks, in two meta-analyses of short trials.

Compared with continuous sitting [7]; prolonged sitting without breaks [8]

Linked to more type 2 diabetes at both short and long sleep in pooled cohorts, a U shape with the lowest risk at 7 to 8 hours a night.

Compared with people sleeping 7 hours a day [5]; normal sleepers [3]; people with normal sleep duration [4]

Linked to more new obesity in short sleepers in pooled cohorts. Long sleep was not linked to obesity in one review and weakly linked in another.

Compared with people with normal sleep duration [6]; normal sleepers [3]; people with normal sleep duration [4]

Shown to lower LDL cholesterol by about 4.8 mg/dL, 3% to 4%, at a median 25 g of soy protein a day against non-soy protein, in pooled trials.

Compared with non-soy protein [4]; control groups the abstract does not describe [5]

Linked to 17% less type 2 diabetes with muscle-strengthening activity in pooled cohorts, with most of the drop by 60 minutes a week.

Compared with people doing no muscle-strengthening activity [1]; lower amounts of resistance exercise [4]; men doing no weight training [5]

Shown to lower HbA1c by about 0.4% to 0.6% with resistance training in type 2 diabetes in pooled trials, more at high intensity, without a clear fasting glucose change.

Compared with control groups in randomized trials [6][7][8]; aerobic training [6]

Shown to lower HbA1c by about 1.5 points more than placebo as single therapy in type 2 diabetes, with no added drop at higher doses.

Shown to lower fasting glucose about 6 mg/dL and triglycerides about 14 to 18 mg/dL, mostly in people with obesity, diabetes or metabolic syndrome. HDL did not change.

Shown to cut deep abdominal fat about 15% more than placebo in adults with HIV on treatment. Fat under the skin did not change.

Shown to add about 1.6 kg of fat-free mass and cut about 1.6 kg of body fat in middle-aged and older men, with no change in weight.

Shown to lower body weight 15% to 21% at 72 weeks in adults with obesity without diabetes, against 3% on placebo, and more than semaglutide.

Shown to lower homocysteine about 1.2 to 1.3 μmol/L at 4 g a day or more in healthy adults. Heart disease was not measured.

Shown to lower weight by about 5.3 kg more than placebo in adults with overweight or obesity, and 3.4 kg in adults with type 2 diabetes, with more adverse events.

Compared with placebo [7][8][3]

Shown to lower fasting glucose about 6 to 10 mg/dL and HbA1c about 0.3 points in adults with prediabetes or type 2 diabetes.

Shown to lower triglycerides about 13 mg/dL and LDL about 6 mg/dL in adults with metabolic conditions. Smaller reviews found no significant LDL change.

Shown to lower weight about 2.5 to 4 kg against control diets in adults, most in adults with overweight or type 2 diabetes.

Compared with the participants' habitual diet, unchanged, in 3 trials in US and New Zealand adults, and in 8 trials a National Cholesterol Education Program diet, American Diabetes Association and Korean Diabetes Association diets, a portion-controlled diet, a Mediterranean diet, a low-fat diet, a healthy omnivorous diet or a high-carbohydrate lacto-ovo vegetarian diet [1]; non-vegetarian diets [2]

Shown to lower LDL cholesterol about 0.24 to 0.30 mmol/L against omnivorous or control diets in adults.

Compared with the participants' habitual diet, unchanged, in 3 trials in US and New Zealand adults, and in 8 trials a National Cholesterol Education Program diet, American Diabetes Association and Korean Diabetes Association diets, a portion-controlled diet, a Mediterranean diet, a low-fat diet, a healthy omnivorous diet or a high-carbohydrate lacto-ovo vegetarian diet [1]; an omnivorous diet [3]

Shown to lower HbA1c about 0.3 to 0.4 points against comparison diets in adults with type 2 diabetes.

Compared with comparator diets the source does not describe [1]; control diets the source does not describe [2]

Shown to lower LDL cholesterol about 0.3 mmol/L against omnivorous diets in adults. HDL also fell slightly in one review.

Compared with control diets the source does not describe [2]; an omnivorous control diet containing meat and dairy products [3]; an omnivorous diet [4]

Shown to lower LDL cholesterol slightly, by 0.09 mmol/L, against refined-grain control foods in pooled trials, with whole-grain oats lowering cholesterol most.

Compared with non-whole-grain control foods [8]; refined grains or placebo [9]

Shown to lower body weight against control diets in adults with overweight or obesity. As one-off self-help instructions, it matched standard brief advice at one year.

Compared with a daily energy-restricted diet or a routine diet [7]; standard brief weight-management advice [8]

Shown to raise HDL cholesterol by about 0.09 mmol/L in trials of adults without heart disease, with no change in triglycerides.

Compared with periods without alcohol [9]

Shown to lower blood uric acid, with 25 of 26 people on 300 mg a day reaching the target within 30 days against none of 25 on placebo.

Shown to lower total cholesterol by about 8 mg/dL against control in adults with overweight, mostly in trials under 6 months.

Compared with control diets the source does not describe [1]; eating freely every day or keeping the present lifestyle [2]; no change in eating times [5]; time-restricted eating [6]

Shown to lower new type 2 diabetes by about 14 to 15%, with 33.1% against 36.8% developing it over 5 years in one valsartan trial.

Shown to lower fasting glucose by about 16 mg/dL and triglycerides in people with prediabetes or type 2 diabetes. Reviews disagree on LDL and total cholesterol.

Shown in two trials to lower triglycerides more than higher-carbohydrate diets in adults with overweight, while a third found similar heart risk changes across four diets.

Compared with the Zone, LEARN and Ornish diets [7]; the Zone, Weight Watchers and Ornish diets [8]; a conventional low-calorie, high-carbohydrate, low-fat diet [9]; a high-carbohydrate, high-fibre diet and the high-protein Zone diet [11]

Shown to lower blood sugar about as much as metformin and other oral diabetes drugs in adults with type 2 diabetes, in mostly low-quality trials.

Shown to lower body weight by about 0.9 kg in adults. A 6-month trial found no change in visceral or liver fat.

Shown to lower LDL by about 0.25 mmol/L in adults on a median 6.5 g a day of barley beta-glucan.

Shown to cut the blood sugar rise after a carbohydrate meal by 23% when oat beta-glucan is added, only at higher molecular weights. These were single-meal tests.

Shown to lower weight by about 1.6 to 1.8 kg in adults, with very high variation. In type 2 diabetes, weight did not change significantly.

Shown to produce about 2.8 kg more weight loss than placebo over 6 to 12 months in obesity trials. Not approved alone for this use.

Shown to lower HOMA-IR and fasting insulin slightly in overweight adults and women with PCOS. Fasting glucose and HbA1c did not change significantly.

Shown to lower body fat and insulin resistance more than exercise alone, mainly in women, people with a BMI of 25 or more and after 4 weeks.

Linked to lower type 2 diabetes, 33% lower at 6 cups a day than no coffee, with decaf too. A genetic study did not support cause.

Compared with people drinking no coffee or rarely [7]

Shown to lower weight by about 1 kg in walking programs built on a step counter, measured mostly before and after in the same people.

Compared with before the program, in the same people [11]; before the program in the same people, and control participants, pooled together [8]; control groups the source does not describe [9]

Shown to improve blood vessel widening and lower insulin resistance in short trials of chocolate or cocoa, in one meta-analysis rated low to moderate quality.

Compared with control conditions the abstract does not describe [3]

Shown to lower LDL cholesterol slightly in adults, by 0.10 mmol/L across trials and 0.28 mmol/L in the original feeding trial.

Compared with control diets the source does not describe [3]; the DASH trial's control diet [6]; usual, low-fat and low-antioxidant diets, behavioral programs alone and usual gestational diabetes care [7]

Shown to lower weight about 1.4 kg more than control diets over 8 to 24 weeks in adults, more in people with overweight or obesity.

Compared with weight-loss, low-fat and usual diets, behavioral programs alone, general heart-failure advice and standard low-sodium blood pressure advice [7]; typical Western or usual diets and other low-energy diets [8]

Linked to about 20% lower rates of cardiovascular disease, coronary heart disease, stroke and diabetes in cohort studies, at low certainty.

Compared with people who followed DASH less closely [7]

Shown to raise lean mass by about 0.45 kg in adults, though a 2-year trial in older adults found no change in body composition.

Shown to lower HbA1c by about 1.0 to 1.2 points against almost no change on placebo in adults with type 2 diabetes, with 62% reaching under 7% against 22%.

Compared with placebo [1]; sitagliptin, metformin, exenatide and insulin glargine [1]; other diabetes drugs in a network meta-analysis [2]

Shown to lower weight modestly in type 2 diabetes, about 0.9 kg more than placebo overall and 1.9 kg at doses above 1 mg, in a meta-analysis of 18 trials.

Compared with placebo [8]; dulaglutide 1.5 mg [3]; semaglutide [4]

Shown to lower triglycerides about 29% and LDL cholesterol 21% and to raise HDL 11% against placebo, with triglycerides 46% to 55% lower in severe high triglycerides.

Compared with placebo [7]

Shown to lower total cholesterol and triglycerides and raise HDL in controlled trials, more in people with diabetes. Sources disagree on LDL.

Shown to lower fasting glucose slightly with kimchi and kefir, in two meta-analyses. Probiotic yogurt did not differ from ordinary yogurt.

Compared with control groups the abstract does not describe [7][9]; conventional yogurt [10]

Shown to lower liver enzymes, LDL and triglycerides with quercetin alone in people with fatty liver disease, at very low to moderate certainty.

Shown to raise blood folate and lower unmetabolized folic acid more than folic acid in women of childbearing age. These are blood markers, not health outcomes.

Shown to lower triglycerides about 24 mg/dL and raise HDL slightly in adults, with no LDL change. One 10-week trial found no lipid change.

Shown to lower fasting glucose, and HbA1c by about 0.5 points, more in people with type 2 diabetes. Insulin did not change.

Shown to lower fasting glucose about 7 mg/dL in adults. In insulin resistance, the result lost significance under another analysis.

Shown to raise hemoglobin by more than 2 g/dL in 44% and 55% of anemic women with fibroids, against 17% and 6% on placebo, in two trials.

Compared with placebo [2]

Shown to raise hemoglobin by more than 2 g/dL in 50% and 62% of anemic women with fibroids, against 16% and 21% on placebo, in two trials.

Compared with placebo [6][8]

Shown to raise hemoglobin before fibroid surgery, by about 0.9 g/dL against placebo or no treatment, and with iron 75% reached target levels against 49% on iron alone.

Compared with iron alone [10]; placebo or no pretreatment [11]

Shown to lower fasting glucose slightly in adults across 50 trials, with no change in HbA1c.

Shown to lower total cholesterol by 2.8 mg/dL in trials of catechin-enriched green tea drinks. LDL, HDL and triglycerides did not change significantly in those trials.

Compared with water or other placebo drinks, no intervention, or green tea drinks low in catechins [4]

Shown to raise fat burning slightly during and after exercise. These trials did not measure body fat.

Shown to lower fasting glucose, HbA1c and insulin resistance modestly with EGCG supplements in adults, with HbA1c down about 0.18 points.

Shown to lower fat mass about 2.1 kg and raise lean body mass about 2.1 kg in healthy older adults, with no change in weight.

Shown to lower visceral fat modestly and raise thigh muscle area with low-dose growth hormone in adults with obesity and no deficiency.

Shown to lower body fat about 2.6 kg and raise lean mass about 1.4 kg in adults with growth hormone deficiency. Quality of life improved in most trials.

Shown to lower HbA1c about 0.5% more than standard-protein diets within 6 months in type 2 diabetes, in one meta-analysis of nine small trials.

Compared with diets with less protein

Shown to lower free and total testosterone and glucose and raise SHBG in women with PCOS. Metformin did better on hirsutism.

Shown to lower BMI slightly, about 0.6 kg/m², and glucose, triglycerides and blood pressure in adults across several conditions, at low certainty for some.

Shown to cut new eye disease by about 76%, kidney protein leakage by 39% to 54% and nerve damage by 60% with intensive insulin treatment in type 1 diabetes.

Shown to lower HbA1c in type 2 diabetes, to 7.0% against 7.9% on diet over 10 years in one trial, with 25% fewer small-vessel complications.

Shown to give HbA1c similar to NPH insulin with fewer people having low blood sugar, while differences in severe episodes were small.

Shown to give the same HbA1c as glargine with fewer low blood sugar episodes, including severe episodes in 4.9% against 6.6% in one large trial.

Shown to lower fasting glucose slightly in adults with prediabetes or type 2 diabetes, while HbA1c did not change overall in pooled trials.

Compared with a control diet with no time restriction [10]; unrestricted eating [11]; daily calorie restriction or a control group [12]; standard-of-care nutritional counseling alone [13]

Shown to halve anemia risk in non-anemic pregnant women, with no change in birth weight or preterm birth.

Shown to lower HbA1c about 0.6 points more than comparison diets at 3 to 6 months in type 2 diabetes, with mixed results at 12 months.

Compared with diets that did not restrict carbohydrates to the level of ketosis

Shown to lower blood glucose about 0.47 mM after single doses, more with monoesters than salts.

Shown to raise serum iron, ferritin and hemoglobin more than ferrous sulfate in people with iron deficiency anemia.

Shown to keep off about 6.8 kg more than placebo for a year after a diet. Only liraglutide plus exercise also improved blood sugar and fitness.

Shown to cut fat mass and visceral fat more than placebo in people with overweight or obesity, with visceral fat down 12 to 23%. Lean mass results varied.

Shown to lower HbA1c and raise remission rates at 3 to 6 months in type 2 diabetes, with no clear difference at 12 to 24 months.

Compared with diets with more carbohydrate

Shown in one meta-analysis of 8 trials to lower BMI and insulin resistance more than a regular diet in women with PCOS.

Compared with a regular diet with about 45% of energy from carbohydrate [13]; before the diet, in the same women [14]

Shown to lower body weight about 1.4 kg against higher-fat diets in adults not trying to lose weight, with larger drops at higher starting BMI.

Compared with diets with more fat

Shown to lower weight about 1.75 kg against control diets in adults, more with calorie restriction or exercise, and to match low-carbohydrate and diabetes association diets.

Compared with control diets the source does not describe [6]; a low-fat diet, a low-carbohydrate diet and the American Diabetes Association diet [7]; a control diet of advice to reduce dietary fat, in Spanish adults [8]; ad libitum Mediterranean diet advice, so both groups ate a Mediterranean diet [9]

Shown to lower blood pressure about 3/2 mmHg and LDL cholesterol and HbA1c slightly in adults, at low to moderate certainty.

Compared with no or minimal intervention, and another dietary intervention the abstract does not name [2]; a low-fat diet, a low-carbohydrate diet and the American Diabetes Association diet [7]; control diets the source does not describe [10]

Shown to lower HbA1c about 1.1 points more than placebo in people with diabetes, and more at higher doses.

Shown to lower fasting glucose about 27 mg/dL and HbA1c about 1 point in adults with type 2 diabetes, in low quality trials.

Shown to raise HDL and lower triglycerides and LDL in people with vascular disease on statins, though events did not fall.

Shown to lower weight about 1.8 kg more than control diets in adults, without calorie limits in the trials that supplied food.

Compared with the participants' usual Western diet, in Swedish adults [3]; an average Nordic diet with the same calories [4]; an average Danish diet, with all food supplied free [5]; control groups the source does not describe [6]

Linked to lower death, heart attack, stroke and type 2 diabetes rates with higher adherence in cohort studies, at low certainty.

Compared with people with the lowest adherence to Nordic dietary patterns, in European cohorts [2]; people with lower adherence to the Nordic dietary pattern [9]; people in the lowest category of Nordic diet adherence [10]

Shown to lower HbA1c by 0.07 percentage points and fasting glucose slightly in people with type 2 diabetes, in one meta-analysis of short trials.

Compared with diets with the same calories without tree nuts [12]

Shown to lower HbA1c by 0.27 points and fasting glucose by 0.44 mmol/L in people with type 2 diabetes, in pooled trials against control groups.

Compared with control groups in the trials pooled [8]

Shown to lower HbA1c by 0.67% with structured exercise training in type 2 diabetes, and by 0.89% with more than 150 minutes a week.

Compared with control groups in randomized trials [7]

Shown in trials to lower fasting insulin and insulin resistance slightly in women with PCOS. Fasting glucose did not change, at very low to low quality.

Compared with usual care or control groups [27]; before exercise, including trials with no control group [28]

Shown to lower LDL slightly, about 0.15 mmol/L, with fasting glucose and HbA1c falling in prediabetes and type 2 diabetes. Results for others disagreed.

Shown to reduce waist size, weight and BMI in people with obesity in one meta-analysis of 11 trials. Body fat percentage did not change.

Shown to lower body weight by about 12% to 19% at 80 weeks in adults with type 2 diabetes, against about 5% on placebo.

Shown to lower HbA1c about 0.9 to 1.1 points more than placebo in adults with type 2 diabetes, with no severe low blood sugar reported.

Shown to lower body weight about 12.7 kg more than placebo over 68 weeks in adults with obesity without diabetes. Tirzepatide lowered weight more head to head.

Shown to lower HbA1c by about 0.38 points when added to insulin in adults with type 1 diabetes, while about doubling the risk of ketoacidosis.

Shown to cut sitting by about an hour a day and lower HbA1c 0.17%, body fat and waist size in trials of people with chronic conditions.

Compared with control interventions [9]; control offices whose workers were told to behave as usual [10]

Shown to raise food intake by about 385 kcal a day when sleep was cut. One trial of sleep extension in short sleepers found 270 kcal less eaten daily.

Compared with a control condition with usual sleep [7]; people who kept their habitual sleep [8]

Shown to lower LDL cholesterol by about 51 to 56 mg/dL with atorvastatin and rosuvastatin, and triglycerides by about 25 to 32 mg/dL.

Shown to raise blood vitamin D in trials of UV and sunlight exposure. Advised sunlight raised it less than vitamin D supplements in one trial.

Compared with before the exposures, in the same people [1]; different UVB doses and skin areas [2]; vitamin D3 800 IU daily or 100,000 IU every 3 months [3]; care homes with no added sunlight [4]

Shown in two meta-analyses to lower LDL cholesterol and triglycerides in people with hypertension. HDL cholesterol results differed between them.

Compared with control groups the source abstract does not describe [5]; no intervention [6]

Shown to lower triglycerides about 12% more than placebo in adults with HIV. These are lab changes, and long-term heart effects are not established.

Linked to 28% less type 2 diabetes with more greenspace exposure in one meta-analysis of mostly observational studies.

Compared with people with lower greenspace exposure [2]

Shown to keep weight off in adults who stayed on treatment, while those switched to placebo regained 14%. Only people who finished a lead-in took part.

Shown to reduce binge episodes by about 1.3 a week and weight by about 4.9 kg against placebo in binge eating disorder, with more withdrawals for safety reasons.

Compared with placebo, with or without psychotherapy [9]

Shown to lower body weight about 2 kg in adults with type 2 diabetes or prediabetes. Reviews disagree on BMI.

Shown to raise hemoglobin before fibroid surgery by about 0.9 g/dL more than placebo, in women taking SPRMs including ulipristal.

Compared with placebo [6]; GnRH agonists [6]

Shown to lower HbA1c by about 0.18 points against control diets in adults with overweight or type 2 diabetes.

Compared with the participants' habitual diet, unchanged, in 3 trials in US and New Zealand adults, and in 8 trials a National Cholesterol Education Program diet, American Diabetes Association and Korean Diabetes Association diets, a portion-controlled diet, a Mediterranean diet, a low-fat diet, a healthy omnivorous diet or a high-carbohydrate lacto-ovo vegetarian diet [1]

Shown to lower weight about 2 to 3 kg against non-vegetarian diets in adults. The lacto-ovo subgroup alone did not reach significance.

Compared with control diets the source does not describe [2]; non-vegetarian diets [5]; untreated control groups, which 4 of the 15 trials had [6]

Shown to raise blood B12 by mouth about as well as injection in people with B12 deficiency. One small trial in children favored injection.

Shown to lower new type 2 diabetes about 15% in adults with prediabetes. In older adults not selected for prediabetes, VITAL found no significant difference.

Shown in one review to lower fasting glucose and insulin slightly against placebo in women with PCOS. An earlier review found changes mainly with other nutrients.

Compared with placebo [71][72]

Linked to 32% lower type 2 diabetes per three daily servings of whole grains in pooled cohorts. Brown rice was linked to 11% lower risk.

Compared with three fewer servings a day, in a dose-response model [6]; the lowest brown rice intake [7]

Shown to lower triglycerides in a meta-analysis of 7 studies. Total and LDL cholesterol were lower only after single studies were removed.

Shown in one meta-analysis to lower cortisol, ambulatory systolic pressure, resting heart rate, fasting glucose and LDL cholesterol more than active control activities.

Compared with active control interventions [11]

Shown in one meta-analysis to lower HbA1c by 0.47 points and fasting glucose by 24 mg/dL in adults with type 2 diabetes, with high heterogeneity.

Compared with control groups including usual care or standard treatment [12]

Shown in one small meta-analysis to lower menstrual irregularity, signs of excess androgens, fasting glucose and insulin resistance in women with PCOS, at low strength of evidence.

Compared with controls the source abstract does not describe [21]; conventional physical activity, routine care or no intervention [22]

Shown to lower fasting glucose about 14 mg/dL and HbA1c about 0.55% in people with and without diabetes.

One small trial found obese adults on 900 mg a day lost weight, ate less carbohydrate and felt full sooner than on placebo.

One trial found adults with binge eating disorder lost 4.9 kg on lisdexamfetamine 50 or 70 mg over 11 weeks, against 0.1 kg on placebo.

Small studies found inhaled and nebulized beta-agonists lowered blood potassium in hyperkalemia, and adding insulin with glucose lowered it more than either alone.

Compared with control groups in small trials, which the abstract does not describe [9]

One trial found 66% of adults at risk of tumor lysis syndrome kept uric acid controlled on allopurinol, against 87% on rasburicase.

One trial found 3 fasting days a week lowered HbA1c by 7.3 mmol/mol against control over 12 weeks in insulin-treated type 2 diabetes.

Compared with eating every day, with no fasting days or daily fasting window

One trial in healthy adults without obesity found 4 weeks of strict alternate-day fasting improved cardiovascular markers, with lower sICAM-1 and LDL after longer use.

Compared with eating every day, with no fasting days or daily fasting window

Limited evidence: astragalus added to treatment lowered fasting glucose in type 2 diabetes, and the decoction lowered HbA1c, in studies of limited quality.

Limited evidence: across 13 trials, higher caffeine intake went with more weight and fat loss, with very high variation between trials.

Limited evidence: in a self-report survey of 2,029 adults on the diet, median BMI fell from 27.2 to 24.3.

Compared with before the diet, in the same people [1]

Limited evidence: survey respondents with diabetes reported a median HbA1c fall of 0.4 points and less diabetes medication use.

Compared with before the diet, in the same people [1], [3]

Limited evidence: triglycerides fell in all 6 followers who started above 130 mg/dL, in a study of 24 people sharing blood tests.

Compared with no comparison group [1]; before the diet, in the same people [3]

Small trials found single injections of CJC-1295 raised growth hormone and IGF-1 for days in healthy adults. No study measured muscle, fat, sleep or recovery.

Limited evidence: insulin sensitivity rose over a season of cold water swimming in women and lean swimmers, in one uncontrolled study of 30 people.

One small trial found LDL cholesterol fell after wet cupping in 47 healthy young men, with no significant change in total cholesterol, HDL or triglycerides.

Compared with no treatment [12]

Small trials found HbA1c fell about 0.5 points. Pooled trials found no change in fasting glucose.

Compared with usual diets, and for fasting glucose also low-antioxidant and weight-loss diets, behavioral programs alone and usual gestational diabetes care [7]

One trial found 4.5 mg lowered HbA1c 0.24 points more and weight 1.6 kg more than 1.5 mg over 36 weeks, with more nausea and vomiting.

Compared with dulaglutide 1.5 mg [3]

One trial in youths with type 2 diabetes found dulaglutide lowered HbA1c by 0.9 points while it rose 0.6 on placebo, with no difference in BMI.

Compared with placebo [5]

One trial's later analysis found fenofibrate lowered uric acid about 20% and nearly halved first gout attacks over 5 years in type 2 diabetes, 2% against 3%.

Compared with placebo [15]

Limited evidence: psyllium lowered fasting glucose and HbA1c in type 2 diabetes but not in normal blood sugar. Other fiber results were small or inconsistent.

Small trials found lower inflammation and insulin resistance markers with 200 mg a day of fisetin in men with obesity, most with training.

One trial of 91 obese adults found lower insulin 2 hours after a glucose drink with fresh grapefruit before meals than with placebo.

Compared with placebo capsules with apple juice [3]

Limited evidence: one Japanese cohort linked 6 or more cups a day to 33% lower odds of type 2 diabetes than under 1 cup a week.

Compared with people drinking under 1 cup a week [6]

One small trial found a larger drop in waist size with a catechin-rich green tea drink than a low-catechin one, in people with type 2 diabetes.

Compared with a green tea drink with 96.3 mg of catechins a day [8]

One small trial found green tea extract shrank fibroids by about a third over 4 months in women with symptomatic fibroids. An uncontrolled study found no size change.

Compared with placebo capsules of brown rice [13]; before treatment, in the same women [14][15]

One uncontrolled study of 10 adults found red blood cells carried more surface charge and clumped less on slides after 2 hours grounded. Blood viscosity itself was not measured.

Compared with blood samples taken before grounding, in the same people [8]

Limited evidence: in women with fibroids, the hormonal IUD lowered bleeding and raised hemoglobin more than the combined pill in one small trial, without clearly shrinking fibroids.

Compared with a low-dose combined pill and oral norethisterone acetate [27]; the levonorgestrel IUD and placebo [28]; comparisons in 11 studies the source abstract does not describe [29]

One trial found new diabetes in 30% on insulin glargine against 35% on standard care, measured about 3 months after treatment stopped.

One trial found that at equal 10% weight loss, liver insulin sensitivity rose two to three times more than on Mediterranean or very-low-fat diets.

Compared with diets that did not restrict carbohydrates to the level of ketosis

One trial found fewer diabetes diagnoses on liraglutide than placebo over 3 years in adults with prediabetes and obesity, 2% against 6%.

One small trial found the Ma-Pi 2 diet lowered fasting and after-meal blood sugar, HbA1c and weight more than a standard diabetes diet over 21 days.

Compared with a standard diet following Italian professional societies' guidelines for type 2 diabetes, Mediterranean in style and with the same calories [1]; the same standard diabetes diet, continued for 6 months [2]; before the diet, in the same people [3]

One large trial found fewer new diabetes cases on the olive oil Mediterranean diet, and cohorts link closer adherence to lower diabetes risk.

Compared with a control diet of advice on a low-fat diet [11]; people with lower Mediterranean diet adherence scores, per 2 points, in 24 cohorts, and a low-fat diet in the one trial (PREDIMED) [12]; ad libitum Mediterranean diet advice, without calorie reduction or added exercise [13]

One trial found more weight loss, 5.0% against 1.8%, and a larger HbA1c drop than placebo in adults with type 2 diabetes.