Fiber
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Glucomannan at 3 g/day (1 g before each meal) has EFSA-approved health claims for weight loss when combined with a calorie-restricted diet. A 2005 meta-analysis found it significantly reduced body weight. It works by expanding in the stomach to increase fullness and reduce calorie intake.
Glucomannan has the distinction of being one of few dietary fibers with an EFSA-approved health claim for weight loss. Multiple RCTs and meta-analyses show modest but significant weight reduction when taken before meals with water. Its mechanism is straightforward: the fiber expands dramatically in the stomach, promoting satiety and reducing calorie intake. Additional benefits for cholesterol and blood sugar are well-documented.
Glucomannan has the distinction of being one of few dietary fibers with an EFSA-approved health claim for weight loss.
| Form | Bioavailability | Best For |
|---|---|---|
| Glucomannan Capsules | N/A (acts in GI tract) | Convenient dosing — take with large glass of water before meals |
| Konjac Powder | N/A | Can be mixed into beverages or used to thicken foods |
| Shirataki Noodles | N/A | Food-form — very low calorie noodles made from konjac; lower dose than supplements |
General recommendation: 1 g three times daily, 30 minutes before each main meal with a full glass of water
Timing: Take 30-60 minutes before meals with at least 250 mL (8 oz) of water
| Condition | Recommended Dose | Evidence |
|---|---|---|
| Weight loss | 3 g/day (1 g before each meal) | Strong |
| Cholesterol reduction | 3-4 g/day | Moderate |
| Blood sugar control | 3-4 g/day with meals | Moderate |
Upper limit: 4 g/day; excessive intake may cause GI obstruction if taken without adequate water
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NOW Foods Glucomannan 575mg
NOW Foods
Safety profile: Generally Safe
Clinical trials show modest weight loss of 0.8-1.5 kg over 5-8 weeks vs placebo when combined with a calorie-restricted diet. Glucomannan is not a magic pill — it works by helping you eat less by increasing fullness. Combined with proper diet and exercise, it can meaningfully support weight management.
Yes, when taken properly with adequate water. The main safety concern is choking or GI obstruction if taken as dry tablets without water. Always use capsules or powder with a full glass of water (250+ mL). Tablet forms have been restricted in some countries. Start with a lower dose and increase gradually to minimize bloating.
Take 1 g (about 2 capsules) with a full glass of water 30-60 minutes before each main meal. This timing allows the fiber to absorb water and expand in your stomach before you eat, maximizing the satiety effect. Do not skip the water — it is essential for both safety and effectiveness.