Six Foods That Diabetics Should Avoid


There’s a whole lot of misleading information around regarding the types of foods that a Type 2 diabetic or someone with prediabetes can eat.

I’ve seen lots of articles from health sites saying eating certain foods or supplements will help in controlling elevated blood sugar levels in Type 2 diabetes. While that may be true, I believe that it’s the overall diet that will make the difference, not just eating 1 or 2 foods or supplements.

So in this article, I’m not going in that direction. Instead, I’m going to list out 6 foods that diabetics should avoid so that they can reduce and control their blood sugar levels and decrease insulin resistance which is the main cause of Type 2 diabetes.


1. Sugar

We know that the high intake of sugar causes not only diabetes but also strokes, heart disease, and cancer. But now it seems there’s more bad news about sugar.

In 2015 Time came out with a news report where Dr. Robert Lustig from the Department of Pediatrics at the University of California San Francisco said that they have come up with the evidence that “sugar is toxic”. Dr. Lustig led a study of 43 Hispanic or African-American children aged 8 to 18 years old where he designed a special diet for them for 9 days. The diet basically replaced most of the sugar with starch leaving 10% of their daily calories from sugar.

The results were startling: overall fasting sugar dropped by 53% and insulin sensitivity improved. Triglycerides and LDL levels were also reduced and they had less fat in the liver!

Another study, also by researchers in the University of California, San Francisco, and reported in Live Science stated that sugar should be as strictly regulated as alcohol and tobacco. They asserted that sugar and sugar products are as detrimental to society as alcohol and tobacco.

In another article published in Times, researchers from the Saint Luke’s Mid America Heart Institute found that amongst all added sugars i.e. starch, glucose, lactose and sucrose (table sugar), fructose was the most harmful in worsening insulin levels and glucose tolerance, both drivers of prediabetes. It causes the most harmful of fat storage – abdominal visceral fat is commonly known as belly fat and promotes other chronic health conditions like inflammation and hypertension i.e. high blood pressure in the body.

The lead researcher Dr James J. DiNicolantonio, said, “We clearly showed that sugar is the principal driver of diabetes,” He continues, “The studies that we looked at clearly show that once you hit 18 percent compared to just 5 percent of your total calories from sugar, there’s significant metabolic harms promoting prediabetes and diabetes,” “In fact, there’s a two-fold increase.” DiNicolantonio says, “It’s refined carbs and added sugars that lead to insulin resistance and diabetes, which leads to high insulin levels, which drives obesity.”

Now if you have Type 2 diabetes, my advice would be also to avoid all other forms of sugar and sweeteners like honey, agave syrup, coconut or palm sugar etc. because all these will also spike your blood sugar and insulin levels.


2. Refined Carbohydrates

Refined carbohydrates such as white bread, white rice, noodles, pasta, pizza and many others break down into sugar in a few minutes after eating. All of them have high glycemic indexes and loads, causing your blood sugar and insulin levels to spike within half an hour upon eating them.

Such refined carbohydrates are stripped of all fiber, vitamins, and minerals and because of this, they are a source of empty calories. Studies show that consumption of refined carbs is associated with inflammation, obesity, insulin resistance and high blood sugar, the last two being the hallmarks of Type 2 diabetes. In fact, in Asia it’s the staples i.e. rice and noodles that are spiking people’s blood sugar levels, increasing insulin resistance and contributing to Type 2 diabetes.

Once a person has Type 2 diabetes the risk of blindness, kidney failure, heart attacks, stroke and lower limb amputation automatically increases. According to the World Health Organization, diabetes is a major cause of blindness, kidney failure, heart attacks, stroke and lower limb amputation. So if folks with prediabetes or diabetes continue consuming refined carbs, the risks of getting these other chronic diseases and dying from them are amplified many times over.


3. All Grains Including Wheat

You need to remove all grains from your diet if your blood sugar is high and have either prediabetes or Type 2 Diabetes. And no, there’s no typo error here. You read it right – you need to remove grains from your diet if you have elevated blood sugar, prediabetes or full-blown Type 2 diabetes.

“But my doctor told me that whole grains are healthy and they provide fiber that’ll help lower blood sugar!” you may say. Yes, whole grains contain fiber; but they also contain non-fiber carbohydrates like starches and sugar that spike your blood glucose levels, promote insulin and leptin resistance. Earlier on, I’ve talked about insulin resistance so you know that it causes Type 2 diabetes, obesity, and metabolic syndrome.

Don’t believe me? Take a bowl of oatmeal then test your blood sugar levels 2 hours afterwards. The next day, for the same meal, substitute the oatmeal with, say, coconut milk and some chia seeds then do the same blood glucose test 2 hours after the meal. You’ll see a difference in the blood glucose readings. This is the same for all grains which are high carbohydrate foods.

Now, let’s talk about leptin, another hormone….

Leptin is produced by the body’s fat cells. Basically what this hormone does is that it tells your brain that you’re hungry when the leptin levels are low and you eat; when your leptin levels are high, it tells your brain that you’re full and you stop eating. This is what happens in the ideal world: after we finish our meals, our leptin levels are high and we stop eating. After a few hours, our leptin levels drop to the point where the hormone “tells” our brains to eat to avoid hunger.

According to Dr. Ron Rosdale, an anti-aging expert, “Studies have shown that leptin plays significant if not primary roles in heart disease, obesity, diabetes, osteoporosis, autoimmune diseases, reproductive disorders, and perhaps the rate of aging itself. Many chronic diseases are now linked to excess inflammation such as heart disease and diabetes. High leptin levels are very pro-inflammatory, and leptin also helps to mediate the manufacture of other very potent inflammatory chemicals from fat cells that also play a significant role in the progression of heart disease and diabetes.”

For folks who have leptin resistance, when the leptin levels are high, the brain somehow doesn’t get the message that they’re full and they continue eating. Or instead of the normal 5 hours it takes for leptin levels dip, the brain somehow gets the message much earlier and hunger or the urge to eat happens earlier.

What has this got to do with grains? Well, because of the high amounts of starch they contain, grains will lead to blood sugar and insulin spikes. Normal insulin spikes are okay if you’re healthy and don’t have any chronic conditions; but if your blood sugar is elevated and you have insulin resistance and prediabetes or Type 2 diabetes, your insulin levels are also elevated, this causes not only constant blood glucose spikes but also excess fat storage and excess fat drives leptin resistance.

In an ideal world when your body stores fat, leptin levels go up and you feel full. But for someone with leptin resistance, the communication between leptin and the brain is somehow broken and the person continues eating even when leptin levels are high because they feel hungry constantly. This is why most folks who are fat and overweight have elevated blood sugar, insulin and leptin resistance and are at risk of diabetes, heart disease and other chronic diseases.

Okay, I can hear some of you protesting, “Hey, but I’m not fat and overweight!” Let me be more specific – if you have a high percentage of bodyfat, you may not be overweight but your risk of diabetes is just as great. This is why Asians get elevated blood sugar levels, insulin and leptin resistance at much lower bodyweights than Caucasians. Tell-tale signs of high bodyfat levels include:

  • For guys – skinny fat i.e. having excess fat around the middle and a protruding belly despite a normal bodyweight.
  • For ladies – carrying excess fat on the waist, hips, thighs and buttocks despite having a normal bodyweight.

Excess fat around the waist or middle is belly fat also known as visceral fat which predisposes a person to chronic diseases such as heart disease, cancer, stroke, dementia, diabetes, depression, arthritis, obesity, sexual dysfunction and sleep disorders.

Without grains, you can still get lots of fiber from seeds, vegetables, and nuts which are much more nutrient dense that any grain you can think of. For example, chia and flax seeds, vegetables such as broccoli, Brussel sprouts, cauliflower, kale, bak choy etc. all contain copious amounts of both soluble and insoluble fiber which will not spike blood sugars much.


4. Root Vegetables

For folks with diabetes or prediabetes, consumption of root vegetables and tubers like potatoes, sweet potatoes, turnips, carrots, yams and taro are problematic because of the concentrated sources of starch and sugar and low amounts of fiber in these foods. These foods will cause blood sugar and insulin spikes. If you’re already a diabetic or have prediabetes, you need to avoid them.

The glycemic indexes of tubers and root vegetables range from moderate to high. The ones with the lowest glycemic index are yams, carrots and sweet potatoes with their GI at 38, 47 and 55 respectively.

Cooking tubers and root vegetables often convert the starches into simple sugars, increasing their GI values further. For example, an uncooked carrot has a GI of only 15 but once it is cooked, the GI can go up to 75, especially if it’s overcooked. If in doubt, test your blood glucose level 2 hours after food – if you’ve eaten a root vegetable, you’ll see a spike in the reading.

The best vegetables for diabetics are cruciferous and leafy vegetables which are full of fiber and very low on carbs. They can be eaten in any amount and besides fiber, they also give antioxidant and phytonutrient protection. Broccoli, kale and cauliflower contain a compound called sulforaphane which offers anti-inflammatory protection against diabetic nephropathy which is damage to the kidneys caused by diabetes.


5. Processed Foods

Processed foods are commonly known as junk food. Not only have they little or no nutritional value, they are filled with sugar, sodium, trans-fats, additives, preservatives, artificial sweeteners, coloring and other chemicals which create havoc to the already damaged metabolic systems of diabetics. In fact, it is the proliferation of processed foods that characterize the typical modern Western diet which has skyrocketed not only the rates of Type 2 diabetes but also heart disease, strokes, hypertension and cancer.

Processed foods have high levels of advanced glycation end-products (AGEs) which cause inflammation and oxidative stress, damaging cells and tissues in the body causing insulin resistance and promoting Type 2 diabetes.

Dr. Jaime Uribarri, a professor of medicine and nephrology at Mount Sinai School of Medicine has conducted extensive research on AGEs and their effects on diabetes patients. He was the chief researcher in one study which was published in the July 2011 issue of Diabetes Care. In that study it was found that AGE consumption contributes to insulin resistance in type 2 diabetes; limiting foods high in AGEs prevents the development of oxidative stress and preserves the body’s natural defenses against insulin resistance.


6. Fruits and Fruit Juice

Fruit juice is often perceived as nutritious and healthy. In fact, nothing is further from the truth.

When you eat fruits, the flesh and the peel contain fiber that slows down the release of sugar into the blood stream, and you get all the vitamins, trace minerals, phytonutrients, enzymes and flavonoids that provide antioxidant, anti-inflammatory protection and other health benefits from whole fruits.

On the other hand, fruit juice contains only water, sugar and a small fraction of the nutrients found in whole fruits. Once the flesh and peel are removed, the fiber also goes so what you essentially get in a glass of fruit juice is nothing more than fruit flavored sugar water. And we’ve seen how harmful sugar is, not only to diabetics but also to healthy folks.

Also, fruit juice doesn’t fill us up unlike whole fruits. When we eat fruits, say, 5 apples, we feel full because of the flesh and fiber. However, when we drink apple juice, the number of apples in a glass of apple juice can be as many as 6 or 7 but we don’t feel full at all since the flesh and fiber have been completely removed.

Now that doesn’t mean fruits are okay for you to eat if you’re a Type 2 diabetic because the sugar in fruits will spike your blood sugar levels. Also, the sugar in fruits is fructose; and fructose has been proven to promote insulin resistance and Type 2 diabetes. And please don’t believe low GI fruits are okay for you either – they will also spike your blood sugar levels if you’re a Type 2 diabetic.

Having said all that, there are 3 fruits that have negligible sugar and carbs and which you, as a Type 2 diabetic can eat: avocados, coconuts (only the flesh, not the coconut water or juice which has sugar) and olives. Coconut milk is okay if there’s no added sugar so please read the ingredients list on the food label.

Once your fasting blood sugar (taken 1st thing in the morning before breakfast) is 5.5 mmol/l (99 mg/dl) or below you can include a handful of these 3 low carb fruits into your diet and see if they spike your blood sugar levels: raspberries, blackberries and strawberries. If they don’t spike your blood sugar levels, then continue having just a handful every day. Lay off if your blood sugar spikes after eating them.


A Final Note….

There are other foods that folks with prediabetes or Type 2 diabetes need to avoid but these 6 already make up about 70% of the forbidden foods list.

By eliminating these 6 types of foods, you’re on your way to better health by lowering your blood sugar and controlling your Type 2 diabetes.



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Galen Chay
I'm a health blogger and have been helping folks online and offline since 2007. I coach folks on how to lower blood sugar, control diabetes and reclaim their health by embarking on the low carb high fat diet and lifestyle. Please visit my website: for more articles on health and nutrition.