Potatoes are a popular type of vegetable and one of the most significant staple foods in the world.
However, their popularity has come into question over recent years, mostly due to the popularity of very low-carb diets.
In this article, we will examine the potential benefits and drawbacks of potatoes.
Are they a healthy and nutritious option? Or is it better to give them a miss?
What Are Potatoes?
Botanically, potatoes are a tuber.
Tubers are an underground storage organ that forms at the bottom of stems from plants. Their primary function is to provide nutrients and energy so that the plant can grow.
Unlike the above-ground parts of the plant, tubers also survive the long and cold winter periods. After the winter finishes, the tuber (potato) develops new shoots that allow the plant to grow above-ground parts once more (1).
Culturally, potatoes have been an important source of food for centuries.
Interestingly, researchers recently found that the first domestication of potatoes occurred between 8,000 and 10,000 years ago (2).
A Worldwide Food
According to an analytical report by Helgi Analytics, potato consumption per capita was 22.6 kg in 2013 (3).
In the United States, potato consumption per capita stood at 51.9 kg in 2013 (7).
Potatoes Are a Good Source of Nutrients
Potatoes are not the most nutrient-dense food in the world, but they offer a fairly good source of nutrients.
Among the various nutrients they contain, potatoes are particularly high in potassium and vitamin C.
The following tables show the full nutritional values for one medium potato (200g), with the data coming from the NCC’s Nutrition Database.
|Saturated Fat||0.05 g|
|Monounsaturated Fat||<0.01 g|
|Polyunsaturated Fat||0.09 g|
|Omega-3 Fatty Acids||0.02 g|
|Omega-6 Fatty Acids||0.06 g|
|Vitamin C||24.0 mg||40%|
|Pyridoxine (B6)||0.59 mg||29.3%|
|Niacin (B3)||2.62 mg||13.1%|
|Pantothenic Acid (B5)||1.02 mg||10.2%|
|Thiamine (B1)||0.14 mg||9.1%|
|Riboflavin (B2)||0.11 mg||6.7%|
|Vitamin K1||1.1 mcg||1.3%|
|Vitamin E||0.12 mg||0.6%|
|Vitamin A||1.17 mcg RAE||0.5%|
Potatoes, Carbohydrate, and the Glycemic Index
One of the common claims against potatoes is that they are high in carbohydrate and have a relatively high glycemic index.
But is that true?
|Apple (medium)||25.1 g||36|
|Blueberries (1 cup)||21.4 g||53|
|Brown rice (100g)||77.2 g||68|
|Potatoes (medium/200 g)||35.8 g||78|
|Whole wheat pasta (100 g)||75.0 g||48|
As shown, gram-for-gram, potatoes are closer to berries than grains in carbohydrate content.
Potatoes are a moderate source of carbohydrate, but they have a high glycemic index.
Potatoes and the Glycemic Index
As shown in the above table, potatoes have a higher glycemic index (78) than many other high-carbohydrate foods.
Dr. Walter Willet, professor of epidemiology and nutrition at Harvard, is a long-standing critic of potatoes due to their high-starch nature (14).
For this same reason, so too are many low-carb and ketogenic diet proponents.
Perhaps there might be a good reason for this when we consider the blood glucose response to potato consumption?
In one study, ten subjects with type 2 diabetes were given 50 grams of carbohydrate either from glucose or cooked potato.
Following consumption, the postprandial blood glucose response of potatoes and pure glucose were very similar (glucose: 8.8 mmol/L; cooked potato 8.0 mmol/L) (15).
But there can be significant variations in glycemic response
Firstly, glycemic responses to the same food can vary from individual to individual (16).
Furthermore, the glycemic index of a meal depends on all the different ingredients rather than just one food. For instance, eating a source of fat and protein alongside potatoes will reduce the glycemic index.
On this note, a study found that boiled and then mashed potatoes had a glycemic index of 108 when eaten alone. The researchers then tried adding chicken breast and oil to the meal, and the glycemic index fell to only 54 (17).
In the context of this whole meal, the glycemic index (GI=54) was similar to a snack of blueberries (GI=53).
Additionally, the way we prepare and cook potatoes can also affect the glycemic index. Cooking and cooling potatoes (and then re-cooking if desired) increases their resistant starch content, and since resistant starch is indigestible, it causes the GI to fall (18).
Potatoes and Chronic Disease
Some people have concerns over potatoes due to studies linking them to chronic disease.
- A dose-response meta-analysis of six studies found a significant association between high potato consumption and type 2 diabetes risk (T2D) (19).
- Three large prospective cohort studies featuring around 200,000 participants demonstrated that greater potato consumption was associated with a higher risk of T2D and hypertension (20, 21).
However… Undoctored Potatoes Are Very Different To “Potato Products”
Despite some of the links between potatoes and chronic disease, it is worth remembering that most of us don’t eat potatoes in a healthy way.
In other words; people eat potato chips and french fries more often than they eat homemade boiled potatoes. This fact could account for some of the negative studies on potato products as a whole.
Additionally, mashed potatoes and potatoes cooked in vegetable oils have different health properties to whole potatoes.
Furthermore, the data on potatoes is not conclusive, and many systematic reviews find no associations with chronic disease;
- A systematic review of 13 studies found no convincing evidence of an association between potatoes and obesity, T2D, or cardiovascular disease. However, there was an association between these conditions and consumption of french fries (21).
- In another systematic review and meta-analysis, there was no significant association between potato consumption and cardiovascular and all-cause mortality risk (22).
- The NIH-AARP study of 566,047 people examined potato intake versus the risk of specific mortality. While high consumption of french fries and potato salad was associated with higher mortality, there was “little evidence that potato consumption is associated with all-cause or cause-specific mortality” (23).
The Studies On Potatoes Are Mixed
As these meta-analyses and systematic reviews show, the data on potatoes is mixed.
Furthermore, it is worth remembering that many potato products contain large amounts of oil, which is a potential confounder. Additionally, by the very nature of potatoes, “people with the highest potato intake” are also likely consuming significant numbers of calories, which is also a confounder.
The studies seem to suggest that a modest/moderate consumption of plain potatoes is not something to worry over.
Do Potatoes Cause Weight Gain?
If you do a quick search on Google, you will see many results discussing potatoes and weight gain.
Can potatoes cause weight gain?
Sure – potatoes are high in both carbohydrate and calories, and eating significant amounts of them probably isn’t good for the waistline.
How about consuming large amounts of oven-roasted potatoes?
The combination of oil and starch tastes delicious, may encourage over-consumption, and it is also very high in calories.
However, a better question is “will potatoes cause weight gain?”
The truth here is that no single food, eaten in reasonable amounts, causes weight gain on its own.
For instance, in a randomized trial, potato intake did not cause weight gain in ninety free-living individuals consuming 5-7 servings of potatoes per week, irrespective of their diet (24).
In a slightly more unusual case study, a two-month potato only diet led to a man called Chris Voight losing 21 pounds of weight (25).
While a potato-only diet may not be the healthiest idea in the world, it shows that potatoes don’t uniquely cause weight gain.
However, bring cooking oil and ultra-processed potato products into the equation, and that may change things.
Watch Out For Green Potatoes
While food allergies and sensitivities can be an issue with any food, adverse reactions to potatoes are rare.
That being said, potatoes contain a chemical compound called solanine. This compound is a type of glycoalkaloid poison that is part of a plant’s natural defense system against pests (29).
When potatoes become exposed to light, their solanine content starts to increase.
At the same time as solanine increases, the chlorophyll content in potatoes also increases. We can see an indication of this from the potato’s green color.
For this reason, health authorities advise avoiding potatoes that look green (30).
The idea of poisonous potatoes may be surprising, but solanine can be toxic in small amounts, and it can build up very quickly. Eating potatoes with high concentrations of solanine can cause severe adverse symptoms (31, 32).
Overall, there are certain groups of people that prefer to avoid potatoes. These groups may include those using strict very-low-carb diets, or those with concern over their glycemic response to potatoes.
It is also worth remembering that some vegetables, such as leafy greens, offer much better nutrient-density.
Other than that, potatoes provide a good source of vitamins and minerals.
Providing we eat them in their unprocessed (and not green!) form, then potatoes are reasonably nutritious.
It’s probably better not to eat too many though.
For more on vegetables, see this guide to root vegetables.