Blood Sugar & Metabolic Health

A cereal grain sold either hulled, with the bran intact, or pearled, with the bran abraded away. The USDA reference entry is for…

Blood glucose response: Some trials report a lower post-meal glucose and insulin response after barley meals compared with refined grains, with a smaller and less consistent effect on longer-term markers.

Rice with the bran and germ left intact, removing only the inedible hull. The USDA reference entry is for raw grain, and rice…

Blood glucose response: Some trials report a lower post-meal glucose rise when brown rice replaces white rice, though the difference is smaller than the wholegrain framing usually implies and varies with rice variety and cooking.

Tiny seeds from a Mexican member of the mint family that form a thick gel when hydrated, because of soluble mucilage in the seed…

Blood glucose response: Some trials report a lower post-meal glucose rise when chia is added to a carbohydrate meal, an effect attributed to the viscous gel slowing gastric emptying. Longer-term glycaemic effects are less consistent.

A pulse eaten whole, ground into gram flour, or blended into hummus, with the large kabuli and small desi types differing in seed…

Blood glucose response: Several trials report a lower post-meal glucose response after chickpea meals than after equivalent portions of bread, rice or potato, with less data on longer-term glycaemic markers for chickpeas specifically.

The hard, bitter seed of a legume-family plant, used whole, ground or sprouted, and responsible for the smell most people…

Blood glucose response: Meta-analyses of randomised trials report reductions in fasting glucose and HbA1c with fenugreek seed in people with type 2 diabetes. The trials are small and heterogeneous, and the doses used are roughly five to twenty-five grams of seed powder a day — many times a culinary amount, and enough to cause digestive side effects.

The green seed of a small desert tree, usually sold roasted in a split shell. The USDA reference entry is for the raw kernel…

Blood glucose response: Some trials report a lower glucose response when pistachios are eaten with a carbohydrate meal, and small improvements in fasting glucose in people with prediabetes.

Dark aggregate fruit of bramble canes, distinguished from raspberries by keeping the central core when picked. Sold fresh in…

Blood glucose response: Some trials report a lower post-meal glucose response when berries are eaten alongside starch or sugar. Blackberry-specific studies are few and short, and no effect on longer-term glycaemic markers has been established.

Small blue-purple berries of the Vaccinium genus, sold fresh, frozen and dried. Cultivated highbush varieties are larger and…

Blood glucose response: Some trials report a blunted glucose and insulin response when blueberries are eaten alongside a carbohydrate load. Longer studies measuring fasting glucose or HbA1c are few and their results are mixed.

A pseudocereal seed from a plant in the rhubarb family, unrelated to wheat and free of gluten. The USDA reference entry is for…

Blood glucose response: Evidence is limited. Small trials report lower post-meal glucose after buckwheat compared with refined grains, and the literature is dominated by short studies with varied preparations.

Dried inner bark from several Cinnamomum species. Almost all supermarket cinnamon is cassia, which contains far more coumarin…

Blood glucose response: Meta-analyses of cinnamon trials in type 2 diabetes report small reductions in fasting glucose, but reviews disagree with each other, HbA1c results are inconsistent, and heterogeneity is high enough that reviewers repeatedly decline to recommend it. Doses are typically one to six grams a day of cassia powder in capsules, which is well above ordinary seasoning use.

The dried fruit of the date palm, around two-thirds to three-quarters sugar by weight, and used both as a fruit and as a…

Blood glucose response: Small crossover studies find that dates produce a lower glucose rise than an equal amount of glucose, probably because of their fibre and polyphenol content. That comparison is a low bar, the studies are small, and it does not make a concentrated sugar source a blood-sugar-friendly food.

A large, bitter-sweet citrus fruit, a hybrid of pomelo and sweet orange. Pink and red varieties owe their colour to lycopene,…

Blood glucose response: Evidence is limited for an effect on glucose control. A small number of trials report lower post-meal insulin when grapefruit is eaten before a meal, but the findings have not been reliably repeated.

Concentrated floral nectar processed and dehydrated by honeybees, composed overwhelmingly of fructose and glucose with small…

Blood glucose response: Some trials report modestly different glucose and lipid responses to honey than to an equivalent amount of sucrose or glucose, and reviews of these are mixed. The differences are small next to the total sugar load, and none of this makes honey a low-sugar option for anyone managing blood glucose.

A tropical stone fruit in the cashew family, with hundreds of cultivars differing sharply in fibre, sweetness and aroma. Eaten…

Blood glucose response: Evidence is limited on how mango affects glucose control. Some small trials report no worsening of glycaemic markers despite the sugar content, but they are short and underpowered for firm conclusions.

A group of small-seeded, drought-tolerant cereals staple across the Sahel and South Asia, sold hulled and cooked like rice or…

Blood glucose response: Evidence is limited. Trials from millet-staple regions report lower post-meal glucose than with refined rice or wheat, but studies are small, varied in which millet species was used, and often conducted by a narrow set of groups.

A summer stone fruit of the Rosaceae family, with fuzzy skin and a single hard pit. Nectarines are the same species differing by…

Blood glucose response: Evidence is limited on peaches and glucose control. Whole fruit generally produces a modest glucose response relative to its sugar content because of its fibre and water, but peach-specific trials are lacking.

A hickory nut native to North America, close relative of the walnut and similarly rich in unsaturated fat. The USDA reference…

Insulin sensitivity: Evidence is limited to a small number of short trials reporting modest improvements in insulin sensitivity markers in adults at metabolic risk.

Milk fermented with Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus, which acidify it until the casein…

Insulin sensitivity: Observational data links higher yogurt intake with lower incidence of type 2 diabetes, but intervention trials measuring insulin sensitivity are few, small and inconsistent.

A pseudocereal seed from a plant related to spinach and beet, cooked and used as a grain. The USDA reference entry is for the…

Blood glucose response: Evidence is limited: small trials report a lower glucose response when quinoa replaces refined grains, but the number of human studies is small and follow-up is short.

A hollow aggregate fruit made up of many small drupelets, harvested from thorny Rubus canes. Fragile enough that most of the crop…

Blood glucose response: Some trials report a smaller glucose and insulin excursion when raspberries are eaten with a starchy meal. The work is early, the trials are small, and effects on longer-term markers have not been established.

A cold-hardy cereal grain used mainly for dense breads and crispbreads in northern and eastern Europe. The USDA reference entry…

Insulin sensitivity: Evidence is limited but interesting: several trials report a lower insulin response to rye bread than to wheat bread despite similar glucose curves, an effect that has not been fully explained.

A drought-tolerant cereal eaten whole, milled into flour or popped, and free of gluten. The USDA reference entry is for the dry…

Blood glucose response: Evidence is limited. Small trials report a lower glucose response to sorghum than to refined grains, plausibly related to its slowly digested starch, but the human literature is sparse.

A starchy storage root in the morning glory family, unrelated to the potato. Flesh colour ranges from white through orange to…

Blood glucose response: Some trials of white-skinned sweet potato extract report small improvements in glycaemic markers in type 2 diabetes. The extract used is not the same as eating the vegetable, and the glucose response to sweet potato itself depends heavily on how it is cooked.

The dried, ground rhizome of Curcuma longa, and the yellow base of most curry powders. The USDA entry is per 100 g of the dried…

Blood glucose response: Some trials of curcumin extracts in people with type 2 diabetes or prediabetes report small reductions in fasting glucose and HbA1c. The trials are short, small, geographically concentrated and use supplement doses; nothing here has been shown for turmeric as a seasoning.

The edible seed of a stone fruit closely related to the peach, eaten raw, roasted or ground into flour and butter. The USDA…

Blood glucose response: Some trials report lower post-meal glucose when almonds are eaten with a carbohydrate meal, and small improvements in HbA1c in people with type 2 diabetes, though results across trials are mixed.

A common bean variety whose dark seed coat carries anthocyanin pigments, staple across Latin America and the Caribbean. The USDA…

Blood glucose response: Several trials report a substantially lower post-meal glucose and insulin response when black beans replace rice or other refined starch in a meal.

A winter squash with dense orange flesh and a hard tan skin, stored for months after harvest. Its carotenoid content rises during…

Blood glucose response: Pumpkin and squash preparations are widely promoted for blood sugar, largely on the basis of rodent studies of concentrated extracts. Human evidence for eating the vegetable is not there.

A cultivated Brassica oleracea grown for its dense head of undeveloped flower buds. Its mild flavour and low carbohydrate content…

Blood glucose response: Replacing rice or potato with cauliflower reduces the carbohydrate content of a meal, which lowers the glucose response for arithmetic reasons. There is little research testing cauliflower itself as an active ingredient.

The dried flower buds of Syzygium aromaticum, one of the most aromatic spices in common use. The USDA entry is per 100 g of…

Blood glucose response: Clove extracts are promoted for blood sugar control largely on the basis of animal studies and one or two very small human studies. There is not enough human research to say anything useful.

The dried fruit of Coriandrum sativum, the same plant whose leaves are sold as cilantro, though the seed tastes citrusy and warm…

Blood glucose response: Coriander seed is promoted for blood sugar control almost entirely on the basis of rodent studies. Human trials are essentially absent, so there is nothing here to rate.

Immature seeds of the pea plant, eaten fresh or frozen while still sweet and starchy rather than dried. Unlike the dried pulses…

Blood glucose response: Some trials report a lower post-meal glucose response when peas or pea-based ingredients replace refined starch, in line with the wider pulse literature.

The large red-skinned variety of the common bean, and the one carrying the highest concentration of the toxic lectin…

Blood glucose response: Several trials report a low post-meal glucose response to kidney beans relative to refined starch, consistent with the wider pulse literature.

Flat pulses sold whole or split, and the only common legume that cooks from dry without soaking. The USDA reference entry is for…

Blood glucose response: Research consistently shows that pulses including lentils produce a markedly lower post-meal glucose response than equivalent portions of potato, rice or bread, and meta-analyses of longer trials also report improvements in fasting glucose and HbA1c when pulses are added to the diet.

Sap from sugar maple and related species boiled down roughly forty-fold until it is about two-thirds sugar, predominantly…

Blood glucose response: Maple syrup is often marketed as a gentler sweetener for blood sugar than table sugar. It is predominantly sucrose, human evidence for a meaningful difference in glycaemic response is minimal, and what exists uses small samples and single meals.

Whole oat groats that have been steamed and pressed flat so they hydrate quickly. The USDA reference entry is for the dry flake;…

Blood glucose response: Some trials report that oats blunt the glucose rise after a meal and modestly improve fasting glucose and HbA1c in people with type 2 diabetes, though trials are short and vary in the oat form used.

The grey-green leaf of Salvia officinalis, used fresh or dried and traditionally paired with fatty meats. The USDA entry is per…

Blood glucose response: Sage extract is promoted for blood sugar control on the strength of a small number of very small trials and animal work. This is not enough to draw a conclusion from.

The aggregate fruit of a low-growing Rosaceae plant, with the seeds carried on the outside. Sold fresh year-round and frozen,…

Blood glucose response: Research suggests strawberry polyphenols eaten with a carbohydrate meal may blunt the post-meal glucose and insulin rise. The studies are single-meal designs, so nothing follows from them about longer-term glycaemic control.

A leafy form of the same species as beetroot, grown for its leaves and thick stalks rather than its root. The coloured stems owe…

Blood glucose response: Chard is often singled out for blood sugar because of a compound called syringic acid. That research is almost entirely in rodents and cell culture, and there is no dependable human evidence behind the claim.

Rice milled to remove the bran and germ, leaving the starchy endosperm. The USDA reference entry is for raw grain; boiling…

Blood glucose response: There is no dependable evidence that white rice offers a blood-glucose advantage. Observational research points the other way, associating high habitual white-rice intake with greater type 2 diabetes risk, though confounding by overall diet is substantial.